When the cast of a beloved movie or TV series reunites years after the credits stop rolling, time stands still for a moment, and fans can't help but get a little emotional.

The old castmates of Lord of the Rings recently had dinner together 15 years after the release of their first film together, and their group selfies made Instagram users lose their absolute minds. In 2014, the cast of Mean Girls broke the Internet with a photoshoot to mark the 10th anniversary of their legendary drama. Whether these monumental meet-ups make your heart skip a beat, or make you feel ancient enough to be somebody's great-grandparent, they're a fascinating look at how the stars change over time. We're looking at you, Lindsay Lohan.

Have a scroll through some of our favourite celeb reunions below, and try to figure out who's older - you, or them.