FaceApp is run by a small team from Saint Petersburg, Russia.

“We developed a new technology that uses neural networks to modify a face on any photo while keeping it photorealistic. For example, it can add a smile, change gender and age, or just make you more attractive,” explains founder and CEO Yaroslav Goncharov, a former head of department at Yandex who is funding the project out of his own pocket.

Goncharov said that FaceApp is unique because they don't apply a filter to selfies, they instead use deep learning technology to change the photo itself.

“Our main differentiator is photorealism,” he explained to TechCrunch. “After applying a filter, it is still your photo. Other apps intentionally change a picture in a way it is entertaining, but not a real photo anymore."

“We believe that such entertaining effects are subject to trends, but photorealism is timeless.”

“In addition to a sound product concept, we think that we are quite ahead in terms of technology. As far as I know, there are no products or research papers that can claim similar quality on this task.”

These constant viral 'challenges' have made the app extremely popular, topping the app store charts in many countries.

There's just something about human nature that delights in the concept, apparently. But how long can it last? Adding a smile or some wrinkles to a selfie can be fun once, but quickly gets boring. Now we've done babies, oldies, and gender-swapping, what's next? Who knows. But boy, I just can't wait to find out.