"Once Upon a Dream" is a song written in 1959 for the animated musical fantasy film Sleeping Beauty produced by Walt Disney. It is based on Tchaikovsky's ballet of the same name, more specifically the piece "Grande valse villageoise" ("The Garland Waltz"). It is the theme of Princess Aurora and Prince Philip and was performed by a chorus as an overture and third-reprise finale. Mary Costa and Bill Shirley, who were cast in the roles of Princess Aurora and Prince Philip, performed the song as a duet