From Yahoo Japan:
Do you ever want to look like celebrities?
"Face Stealer" will turn your face into someone else in REALTIME.
You can transform your face into anyone from celebrities, your friends, lover, Mona Lisa to anime characters.
The app engages with your facial expressions and replaces your face with another person's face in real-time, which let you feel like being someone else.
How to use the app is simple: just choose the face you want to transform and put your face into the iPhone's front camera. That's it!
Enjoy looking like another person, changing your expression or moving your head.
You can take photos of your transformations and send them via Email or share on Facebook, Twitter and Youtube.
You can either take a picture or search for images in order to transform.
* iPhone 4S, iPod touch 5th generation or later is recommended for best performances.