Who sings this song and where can I find it? It's called "One" and a blonde girl sings it...?

I just saw this video on MTV and saw the song was called "One" but missed the artist, and can't find the video anywhere! The song has LOTS of repetition, it constantly says, "one one one one one one" and other words like "stop stop stop stop" and "knock" (i think). The video is mostly white and has a pretty blonde girl singing, any ideas????