A dream ballet, in musical theater, is an all-dance, no-singing production number that reflects the themes of the production. The plot, themes, and characters are typically the same—although the people playing the characters may be different, as the roles of the dream ballet are usually filled by well-trained dancers rather than actual actors.
Dream ballet sequences exist mainly for clarification, foreshadowing, and symbolism, and occur outside the continuity of the production. They also advance the plot of the story through dance. Dream ballets also provide the opportunity to impress the audience with advanced dancing techniques and elaborate staging that would otherwise be impossible or dramatically inappropriate.
The dream ballet is thought to have originated in Rodgers and Hammerstein's 1943 musical Oklahoma!, which includes an 18-minute first-act dream ballet finale choreographed by Agnes de Mille, but dream ballets were devices of music-theatrical productions well before 1943. The technique has since become a routine (although by no means universal) theatrical practice.