[TOMT] [song] Yooouuuuuuuuuu...

I'm trying to remember the name of this song. It sounds very quiet, echo-y, and a bit spacey. It has a female vocalist, and all I can recall from it is that when it gets to the chorus she sings "youuuuuuuuuu" in a very drawn out fashion. It sounds quite beautiful. I believe it was used in a movie's soundtrack, but I cannot recall the movie. Can anyone figure this out based on these few details?