We tried Microsoft's age-guessing app on some famous babies

How-old.net, the site currently taking the internet by storm, claims to work out how old its users are by analysing their photos with Microsoft's face detection software.

While it's a lot of fun and sometimes does get it right, it can be very, very wrong.

With that in mind, we decided to try it out on some other babies.

Prince George

Blue Ivy

Kanye West

Baby Arnie

Prince William

Baby Harrison Ford

Baby Zac Efron

More: Everyone should hear what Kim Kardashian has to say about Bruce Jenner