Heath Ledger is often mentioned as the best actor to portray the biggest enemy of Batman, The Joker. Maybe it was because he used method acting and let the character overrun him. Heath Ledger would practice method acting regularly and to turn into The Joker he locked himself away for weeks to catch the insanity of the character.

He even asked his co-star Christian Bale to actually hit him during the interrogation scene. Christian remembers, "He was slamming himself around, and there were tiled walls inside of that set which were cracked and dented from him hurling himself into them. His commitment was total."

Jamie Foxx started out as a comedian performing in clubs but quickly rose to fame as an awarded actor. He won his Oscar for Best Actor in 2005 for portraying the rhythm and blues musician Ray Charles in the 2004 movie Ray.
 
To prepare for this role, the actor lost 30 pounds (13 kilograms) to have the slender physique the musician had. What is more, Ray Charles was blind, so the film director Taylor Hackford thought that it would be a good idea to glue Jamie Foxx's eyes shut for the whole 14 hours they were filming in a day. The actor agreed and had to wear prosthetic eyelids that were modeled from Charles' own eyelids.
 
The actor reported that it was quite claustrophobic and he felt as if he was a prisoner in his own isolated world, but it made him portray the musician so brilliantly, he received the most prestigious award in the acting industry.

Christian Bale is known for his crazy body transformations. The most famous case is when he lost 55 pounds (25 kilograms) in four months to play Trevor Reznik, who became emaciated due to his insomnia, in the 2004 movie The Machinist.
 
To achieve the skeleton-like stature of a sick person, Christian Bale was just smoking cigarettes and drinking whiskey. Later he 'enriched' his diet with black coffee, an apple and a tin of tuna every day.
 
When the actor reached 99 pounds (45 kilograms), the film producers managed to convince him to stop for health reasons. Considering the man's height is 6 feet (187 centimetres), he was severely underweight and after years of gaining and losing weight as well as training for different roles, Christian Bale realized that at some point he had to stop as it was not beneficial to his health.

Anne Hathaway was casted for the role of Fantine in the 2012 movie Les Misérables based on the novel of the same name by Victor Hugo. The actress was playing a mother living on the street who had to sell her hair, teeth, and eventually her body to support her daughter Cosette.
 
Anne Hathaway made some sacrifices of her own to be a convincing character. She said, "I had to be obsessive about it — the idea was to look near death. Looking back on the whole experience — and I don't judge it in any way — it was definitely a little nuts. It was definitely a break with reality, but I think that's who [my character] Fantine is anyway."
 
She lost 25 pounds (11 kilograms) in two weeks by eating only dried oatmeal paste. Also, she didn't settle for a wig and cut her hair off. The makeup artist and the director tried to talk her out of it but the actress thought it would help her comprehend the mother's state better. Well, she absolutely did as she was awarded an Oscar for Best Supporting Actress.

In 1998 Johnny Depp got the role of Raoul Duke in the movie Fear And Loathing In Las Vegas. The character Raoul Duke was based on a novel by Hunter S. Thompson with the same name and in the movie, he and his friend Dr. Gonzo go on an adventure through Las Vegas as they explore it under the influence of psychoactive substances.
 
The actor and the writer got along really well, so Johnny Depp wanted to do his character who was loosely based on the writer justice. Johnny Depp moved into the basement of Thompson's Aspen house for several months. The writer also let his friend pick some clothes from his wardrobe for shooting.
 
Johnny Depp spent so much time with his character and got so into it that many of the little tics that the actor adopted stuck with him even in real life and can be noticed in later movies.

The actor who played the musician Wladyslaw Szpilman in the 2002 movie The Pianist was Adrien Brody. The movie tells a story of a Polish-Jewish pianist who was a Holocaust survivor and the actor was waiting for such a serious role to fall in his lap.
 
At the same time, he felt that he had a very responsible job to do and wanted to do it justice. To prepare for the role, the actor lost 30 pounds (13.6 kilograms) because he believed that "you can't act emaciated, you have to become emaciated." He also moved out from his apartment and gave up his car, he disconnected from the world by not using a cell phone. He went as far as breaking up with his then-girlfriend and learned how to play Chopin on the piano.
 
Adrien Brody won an Oscar for Best Actor at only 29 years old. But he confessed that the character didn't let him go even after the shooting was done, "I was depressed for a year after 'The Pianist,'" he said. "And I don't suffer from that, generally. It wasn't just a depression; it was a mourning. I was very disturbed by what I embraced [in making that film], and of the awareness that it opened up in me."

The movie Taxi Driver (1976), which starred Robert De Niro, shows a 26-year-old Vietnam war veteran trying to deal with his post-traumatic stress disorder living alone in New York and earning his living as a taxi driver.
 
Robert De Niro is known for dedicating himself to his characters. And for this particular role, he decided to try out the profession of a taxi driver for himself and he got a real cab driver's license. He worked at a cab firm in New York for a month before the filming started. The actor worked 12-hour shifts and according to some people, he didn't completely stop and would go to the streets on breaks in between filming.

Michael B. Jordan was the main villain in the Black Panther (2018) movie. He portrayed Killmonger, a man who seeks revenge for his parents who were killed when he was young. Because of that, he leaves Wakanda and grows up outside his native country to later return and bring justice to his parents.
 
When the actor found out the story of his character, he thought Killmonger must have felt very lonely having to live a life holding a secret that he originated from a country no one knew existed. Michael B. Jordan decided he had to be by himself to understand that feeling. He completely isolated himself from people, but that actually took a toll on his mental health and it was hard to get back to himself after the filming finished and he needed to see a therapist to help him out.

Daniel Day-Lewis is the star of the 1989 biographical comedy-drama My Left Foot and embodied the main character, Christy Brown, who was an Irish writer with cerebral palsy who could use only his left foot so he had to teach himself to write and draw with it.
 
To make the portrayal more convincing, the actor went into character as soon as he reached the shooting set. He asked to be wheeled around the set in his wheelchair, and he wanted to be spoonfed as well as lifted by the staff members. This dedication required some sacrifices: Daniel Day-Lewis damaged two ribs during filming from hunching in his wheelchair for the long weeks that the shooting continued. The actor also learnt to paint using a knife held between his toes. These efforts really paid off as he won an Oscar for Best Actor.

Hilary Swank portrayed Mary Margaret "Maggie" Fitzgerald, an aspiring boxer in the 2004 sports drama Million Dollar Baby. To be convincing in that role, the producers asked Hilary to gain 10 pounds of muscle mass, but she gained 19 instead.
 
To obtain the physique of a boxer, she trained six times a week, dedicating two and a half hours to boxing and an hour and a half to two hours to lifting weights. On top of that, she was strictly following what she ate as to gain muscle she had to maintain a high protein intake.
 
But the training led to the actress getting blisters and she was popping them in the bathtub, which resulted in an infection that almost reached her heart, which would have been detrimental.

The 2020 movie Ammonite is loosely based on the life of British palaeontologist Mary Anning, who is portrayed by Kate Winslet. The movie is set in the 1840s and the character was living with her ill mother and mostly was alone. Kate Winslet didn't want to act like Mary, she wanted to become Mary, so she tried out a little bit of method acting.
 
She lived in a shabby house on the beach while they were shooting the film and she says, "It was so isolated, cold and rattly that when there was a big storm, the waves would hit the windows of the house and the power would go down and I would lie there thinking, 'Kate, what are you doing? Just go to the hotel with everybody else.'"

Robert Pattinson got the role of a 19th century lighthouse keeper in the movie The Lighthouse (2019) and he experimented with method acting to better get into the character. The character slowly surrenders to insanity while staying in the lighthouse during a storm together with the island's longtime keeper, Thomas Wake, portrayed by Willem Dafoe.
 
The actor said, "It was crazy. I spent so much time making myself throw up. Pissing my pants. It's the most revolting thing. I don't know, maybe it's really annoying." He was so completely devoted to the role that he wasn't afraid to "just be sitting on the floor growling and licking up puddles of mud."
 
Robert Pattinson tried to explain how he managed to go wild for the role and he isn't entirely sure how, but it might be related to getting famous at such a young age. He said, "You're hiding a lot, so [on set] you have an excuse to be wild. It's like being an adrenaline junkie."

In the 2006 movie The Last King Of Scotland, Forest Whitaker played the main character, Ugandan President Idi Amin, for which he won the Academy Award for Best Actor. To better understand what he was going to portray, the actor immersed himself in research. He talked with Amin's friends, relatives, generals, and victims. He learnt Swahili and perfected an East African accent.
 
He was so consumed by this role even off-set that his family stopped talking to him as they didn't want to put up with him. He ate only mashed bananas and beans and somehow managed to gain 50 pounds in the process to be more similar to the real dictator in appearance as well.
 
The director Kevin Macdonald said that he was a bit worried because he mostly had experience with documentaries and didn't work much with actors. The director shared his impressions, "This was method acting taken to extremes and I watched with astonishment. Forest was at a crisis point in his career and this felt like make or break. For nearly six months he wanted to be Amin, not just perform him. But in the end I could see there was method in the madness - he acted at the top of his game."

Mickey Rourke was chosen for the role of Iron Man's enemy Whiplash in the second movie of the series. The character was a Russian scientist and a former prisoner, so the actor did a lot of preparing for the role, even though he didn't really get along with Marvel and they didn't consider his suggestions about how he would like to portray Whiplash.
 
He went to a Russian prison to see what it looked and felt like. He also was very interested in the inmates' tattoos. On top of that, he was studying the Russian language every day for three hours. He trained not only his mind but also his body to achieve the menacing strong villain look.

Ashton Cutcher portrayed Steve Jobs in the 2013 movie Jobs. To get to know his character better, Ashton Kutcher went to extremes Steve Jobs himself went to, but that caused the actor to end up in the hospital not just once, but twice. What led him to ruin his health was the fruitarian diet.
 
The actor found out that the Apple co-founder experimented with sometimes sticking to one fruit only, like apples or grapes, without eating anything else. Or drinking only carrot juice. This dedication meant that Ashton Cutcher developed pancreatitis and it was so bad he had to go to the hospital and not just once, but twice.

Nicolas Cage played one of two friends, Alfonso "Al" Columbato, in the 1984 drama Birdy, depicting what they went through serving in the Vietnam War. Cage's character got injured from a bomb and when he got hospitalized, he had his face bandaged. The actor was living with that bandage for about a month and when he took it off, his face was messed up as the bandage caused acne and ingrown hair.
 
The actor had an even crazier idea of how to get into character better. He had an appointment planned to pull out 2 teeth and it was during the shooting. Wanting to see what it felt like to have a hurting face, he decided that he didn't need anesthetics. Nicolas Cage told the Telegraph, "They were baby teeth. So I took advantage of it and had them out. I thought it would add an interesting dimension to the role."

Leonardo DiCaprio won his first Oscar after being nominated for it several times previously for his portrayal of Hugh Glass in the 2015 movie The Revenant, which was based on a real story of a man getting attacked by a bear and then left by his friends because they thought he was dead.
 
For this role, the actor, who is a vegetarian and an environmentalist, was ready to go as far as needed. He slept in a dead animal's carcass and he volunteered to eat raw bison meat. The team actually prepared a faux bison liver from jelly, but the actor feared that it wouldn't be authentic enough and the people in charge figured out all the technicalities so that they could have real meat. The part in the movie when DiCaprio eats the raw bison liver is the first take and the actor's genuine reaction to trying to eat it.

Sylvester Stallone's name is synonymous with Rocky's as the franchise was very popular, grossing more than $1.7 billion at the worldwide box office. Part of its success can definitely be attributed to the actor's dedication to the character. He followed a very strict diet and exercising regime to maintain the fictional boxer's physique and one time, his striving to be as realistic as possible landed him in the hospital.
 
While filming Rocky IV, Stallone encouraged his co-star, Dolph Lundgren, to actually punch him with all his might. The actor explained that Lundgren's uppercut "caught the ribs and hit the heart against the ribcage." To recover from that, Stallone stayed at the hospital for nine days and didn't continue to receive real punches.

Shia LaBeouf's experience of shooting the 2014 movie Fury was an extreme one, but he made it so himself. The movie is set during World War II and LaBeouf's character was Technician fifth grade Boyd "Bible" Swan, tank gunner.
 
For this role, the actor pulled his completely healthy tooth. He shared that it was actually hard to find a dentist who would do that. He also was constantly opening up slash wounds on his face with a knife, despite there being a crew of professionals who could recreate the same effect. What is more, he enlisted in the military and became a chaplain's assistant to Captain Yates for the 41st Infantry.
 
He was so into the character that he was sitting in the tank all the time, even though someone else could have been operating it as the driver was not seen from the outside. Shia LaBeouf also didn't shower and because of his behavior wasn't very liked by others, so he was accommodated separately from other members of cast and crew.

Jason Pollock was an American painter who is known for his "drip technique" in which he splashed paint all over the canvas.
 
In 2000, actor Ed Harris was chosen to portray the artist in the biographical movie Pollock. For this role, Ed Harris actually learnt how to paint. He would regularly visit galleries and just stare at the original paintings. He built a studio at his home in Malibu and tried out the unique technique that made the artist so famous. The actor knew such details like what cigarettes the artist liked and switched to the unfiltered Camel ones to get nearer to the painter. Harris visited the Pollock-Krasner House in East Hampton, NY, and slept in Pollock's actual bed. To make an even more convincing character, Ed Harris gained weight to portray the painter in his final years before he died at age 44 in a single-car crash.

Jim Carrey fully dedicated himself to the role of entertainer Andy Kaufman in the biographical movie Man On The Moon. The character never let go of the actor even when the shooting was done for the day.
 
The actor insisted on being called Andy all of the time on the set, or Tony, the comedian's obnoxiously rude lounge singer alter ego. He didn't break character even when Kaufman's family visited the production. One of the most memorable moments was when Jim Carrey was in Tony mode. He found the keys from Danny DeVito's trailer and locked it from the outside. The he drove a car up to the door of the trailer to block it and then threw away the keys into Los Angeles River.

Gary Oldman had been asked to play Winston Churchill a couple of times before and finally, he agreed to do so for the 2017 movie Darkest Hour. The main concern was the Prime Minister's bigger frame, as the actor wasn't planning on gaining so much weight. But the problem was solved with a special fat suit.
 
Although Oldman ruled out gaining weight, he wasn't as opposed to depicting a not very healthy habit of Churchill's–smoking. He smoked at least 400 Romeo y Julieta Cubans, which were the Prime Minister's favorite, and he actually got nicotine poisoning. But the director of the film, Joe Wright, remarked, "It's Winston Churchill. You can't have Winston Churchill without a cigar."
 
The actor explained how he managed to smoke $20,000 worth of cigars: "You'd have a cigar that was three-quarters smoked and you'd light it up, and then over the course of a couple of takes, it would go down, and then the prop man would replenish me with a new cigar — we were doing that for 10 or 12 takes a scene."

Marlon Brando is the one who popularized method acting and he practiced it from the first roles he got on the big screen. He debuted in the 1950 movie The Men in which he got the main role of an ex-military man Ken Wilocek who got injured and was paralyed so he was left bound to a wheelchair.
 
To prepare for the role, Brando trusted that method acting would help him succeed. So he spent a month at the Birmingham Army Hospital in Van Nuys, Los Angeles living with paraplegics to prepare for playing an injured soldier.

Halle Berry's first movie role was in the 1991 movie Jungle Fever where she played a small role of a drug addict. Despite it being a second-plan role, the actress took it seriously, wanting to prove that she had what it took to be a movie star. How did she decide to do that? She said, "I played a crack addict, and in order to do that, I was living on the streets. So I decided I was going to see what it would be like. I didn't shower or take a bath for like two weeks." The actress said that the other crew members were nice, but she noticed that they started to distance themselves from her.

Will Smith became Paul Poitier for the 1993 movie Six Degrees Of Separation. His co-star was Stockard Channing, who played Ouisa Kittredge, and even though she was more like a mother figure in the movie, Will Smith actually fell in love with her even though he had recently married Sheree Zampino and had a baby with her.
 
The actor confessed, "The movie was over and I went home, and I was dying to see Stockard. I was like, 'Oh no! What have I done?' That was my last experience with method acting, where you're reprogramming your mind. You're actually playing around with your psychology. You teach yourself to like things and to dislike things." Will Smith promised himself that he wouldn’t use method acting ever again.

Dustin Hoffman played one of the main roles in the movie Kramer vs. Kramer (1979). He was the husband who was divorcing his wife, played by Meryl Streep. Sometimes Dustin Hoffman got into character too much and was trying to provoke Meryl Streep.
 
He actually slapped her without warning and everyone around thought that everything was over and they would get sued on top of that. However, Meryl Streep carried on with the scene. But Hoffman wasn't done. When Meryl Streep's character was alone crying in an elevator, Dustin Hoffman was standing off-screen and taunting the actress about John Cazale, her real-life partner who had died a couple of years prior. The actress commented that if Hoffman wanted to use emotional recall, he should use it on himself and not her.
 
Another time, Hoffman took a wine glass and shattered it against the wall, genuinely startling Streep. She remarked that if he wanted to do that, it would have been nice to warn her. He was doing all these things to get Streep to act like he thought she should, provoking genuine reactions when she thought she could do that just fine by herself.

South Korean actor Choi Min-sik who played the protagonist Dae-su in the thriller film Oldboy wasn't afraid to try anything to portray his character convincingly. He lost and gained weight depending on the filming schedule. He also trained for his role and was able to do most of the stunts by himself.
 
One of the most extreme things he did was burning himself with a hot wire because he didn't trust makeup artists to make the burns look real enough.
 
Another thing that not everyone would be brave enough to do is eat a live octopus, let alone four. That is how many Choi Min-sik ate, because he had to do four takes of the scene. This is real dedication, as the actor is vegetarian and a Buddhist, so he apologized and said prayers for each of the octopuses before eating them.

House Of Gucci is a recently released movie about the relationship between Patrizia Reggiani and Maurizio Gucci. The main character, Patrizia, is portrayed by Lady Gaga, who had to embody Patrizia Reggiani, the ex-wife of Maurizio Gucci, the head of the fashion house Gucci.
 
To make her performance the best, Lady Gaga told British Vogue that she was living as if she was Patrizia, "I lived as her for a year and a half. And I spoke with an accent for nine months of that." She added, "Off camera [too]. I never broke. I stayed with her."
 
Lady Gaga said, "It was nearly impossible for me to speak in the accent as a blonde," she continues. "I instantly had to dye my hair, and I started to live in a way whereby anything that I looked at, anything that I touched, I started to take notice of where and when I could see money. I started to take photographs as well. I have no evidence that Patrizia was a photographer, but I thought as an exercise, and finding her interests in life, that I would become a photographer.'

Jamie Dornan is the actor who played the serial killer Paul Spector in the crime drama series The Fall. Normal people usually don't know what goes on in a psychopath's head so the actor decided to do a little experiment and he actually followed around a woman on the London underground.

He described what it was like, "I really kept my distance … she got off a few stops earlier than I was planning so I said right, I have to commit to this. I followed her around a couple of street corners and then was like: what are you doing? It felt kind of exciting, in a really sort of dirty way. I'm sort of not proud of myself. But I do honestly think I learned something from it."

Jared Leto portrayed The Joker in the 2016 movie Suicide Squad based on DC Entertainment comics. He had only about 10 minutes of screen time, but the actor wanted to leave an impression in that limited amount of time, so he let the craze into his real life too.
 
Will Smith remembers that Jared Leto never talked to him outside the scenes they were filming. They didn't even greet each other or say goodbye. Will Smith also thought that it was wrong for Jared Leto not to come to rehearsals, but eventually he realized that he didn't have to as he didn’t even need to act like The Joker because he became him. Margot Robbie, who played the Joker's love interest, Harley Quinn, received a live rat from the actor and after getting over the initial disgust, she kept it as a pet. Viola Davis, who played the government official Amanda Waller, told Vanity fair, "He had a henchman who would come into the rehearsal room, and the henchman came in with a dead pig and plopped it on the table, and then he walked out. And that was our introduction into Jared Leto."