 The song "All Star" by Smash Mouth (qv), heard during the opening  credits, was never intended to be in the final cut of the film. It  was used as a place holder in test prints until a new song could be  found. But test audiences loved it, and the producers kept it in.  When the producers decided to keep "All Star" they figured they  should ask SmashMouth to sing the last song in the movie, "Im a  Believer."