"Once Upon a Dream" is a song adapted from the "Grande valse villageoise" (also known as the "Garland Waltz") in Pyotr Tchaikovsky's ballet The Sleeping Beauty, composed in 1889 on commission from Ivan Vsevolozhsky for the Imperial Theatres in St. Petersburg. The original ballet score, choreographed by Marius Petipa and based on Charles Perrault's fairy tale, is among Tchaikovsky's most celebrated works alongside Swan Lake and The Nutcracker. The waltz melody from Act I was adapted by George Bruns for Disney's 1959 animated film Sleeping Beauty, with lyrics added by Jack Lawrence and Sammy Fain. In the film, it was performed by Mary Costa as Princess Aurora. The melody retains the sweeping, romantic character of Tchaikovsky's original, with flowing phrases in waltz time that convey a sense of fairy-tale enchantment and nostalgic longing. Its graceful, dance-like quality and singable contour have made it one of Disney's most enduring musical moments. While not part of the traditional jazz repertoire, the tune has attracted jazz musicians drawn to its strong harmonic foundation and lyrical possibilities. Lana Del Rey recorded a darker, atmospheric interpretation for the 2014 film Maleficent, demonstrating the melody's adaptability across stylistic contexts. The song bridges the worlds of nineteenth-century ballet, mid-century film music, and contemporary popular song.