Think a song titled Ew! couldn’t be catchy? Wrong!

Jimmy Fallon and will.i.am have taken the Tonight Show host’s notorious sketch Ew and turned it into a song… and it’s already stuck in our heads!

In the you-need-to-see-it-to-believe-it clip, watch as the pair dress up as their 13 year old alter-egos, Sara and mir.i.am.

Best part is – by downloading the song on iTunes, you’ll help support the SeriousFun Children’s Network and i.am.angel Foundation.

Want more? Here's one of our fave moments from Jase & Lauren – they’re always up to something! Weekdays from 6AM on KIIS 101.1!