Please help with this song!

Hey, there's a song I've heard a few times on the radio and I can't find out who sings it. I saw the music video once and all I remember is that the guy lead singer has some people over at his house and he's on top of a grand piano singing and dancing or something. Actually, I just heard the song today and it was at the end of a trailer for the movie I Now Pronounce You Chuck and Larry, with Adam Sandler. It's a different sounding song, kind of upbeat, and repeats the words, "Why don't you like me..." a number of times. I guess that's the best way to describe it. But if you watch that trailer on YouTube or something you'll hear the song and maybe be able to help me out. Please help me someone! Thanks!

Mika - "Grace Kelly"

YouTube - Mika Grace Kelly