I need help finding out who this singer is!

Ok so i was just in American Eagle like on the 23rd and i saw this awesome song its a chick singing it idk the name of the song or artist, but she is like waking around and she is bigger than everything else. Its a really creative song I think her name might have a K-T in it im not sure but its a girl i know that. HELP! please and thanx

suddenly I see- KT Tunstall

YouTube - KT Tunstall - Suddenly I See
link^