One of the film’s iconic scenes – when Briar Rose meets Prince Phillip for the first time to the tune of “Once Upon a Dream” – was called Sequence 8 when it was being produced. It was a particularly hard sequence to get right (Walt Disney rejected it several times) and ultimately had to be done four times, almost bankrupting the studio in the process.
Much of the musical score is based on Pyotr Ilyich Tchaikovsky’s ballet “Sleeping Beauty”. The musical score throughout the film was recorded by the Berlin Symphony Orchestra. The ominous piece of music to which Maleficent hypnotizes Aurora into pricking her finger is called “Puss-in-Boots and the White Cat”. In Tchaikovsky’s ballet, it is used for a comic number in which two cats snarl at and try to scratch each other. Various movements from The Sleeping Beauty ballet underwent some reworking for the Disney film. The opening song (“Hail to the Princess Aurora”) is actually the ballet’s second movement, after the overture. Also, the theme playing when the three fairies clean the cottage is based on “The Silver Fairy” movement, which, in its original form, is barely a minute long.
Bill Shirley and Mary Costa (who were cast in the roles of Princess Aurora and Prince Philip) auditioned together to ensure that their voices complemented each other’s. – IMDB
“Once Upon a Dream” was covered by the American girl group No Secrets in 2003 for the two-disc DVD release, and by Emily Osment in 2008 for the Platinum Edition release, and also by American singer-songwriter Lana Del Rey for the dark fantasy film Maleficent (2014), which serves as a prequel to and re-imagining of the original Sleeping Beauty (1959). Angelina Jolie, who plays the film’s lead role, picked Del Rey herself to perform the song. – Wikipedia