Jimmy Fallon hasn't disappointed when it's come to having fun guests visit The Tonight Show, and Billy Joel only proves that more. Seriously, leave it up to those two to create a doo-wop duo.

This video will have you laughing, singing along and wanting to be best friends with Jimmy and Billy. Check out how they managed to use an iPad app to create an incredible doo-wop duo and sing 'The Lion Sleeps Tonight' here: