Before the decision was made to dub most of her vocals, Rosalind Russell attempted to do her own singing. The highly unsatisfactory results can be heard as an extra feature on the soundtrack CD. After Ethel Merman's death, a tape of the Russell recordings was found in a box in Merman's closet. Merman, who was infuriated that she had not been cast in the film, evidently had retained this copy of the Russell vocals as a strange and somewhat vengeful consolation prize.
During the rehearsals for Gypsy (1962), Mervyn LeRoy was not happy with the girl that he had cast to play "Dainty June". (This was before Ann Jillian was cast.) He thought that the actress was not as good of a dancer or singer as Morgan Brittany, who played "Baby June". He tried to make Suzanne look old enough to play "Dainty June" by having Orry-Kelly design older clothes with padding and having her wear high heels, but the transformation didn't work, she still looked too young to play opposite Natalie Wood, so another casting session brought the role to Ann Jillian. Ann was not really a dancer but her voice was spectacular and Mervyn felt that she made a more believable older June.
The original Broadway production of "Gypsy" opened at the Broadway Theater on May 21, 1959 and ran for 702 performances starring Ethel Merman and Jack Klugman. "Gypsy" was nominated for the 1960 Tony Award for the Best Musical.
Most of Rosalind Russell's songs were dubbed by Lisa Kirk. However, Russell's voice can be heard in "Mr. Goldstone", the reprise of "Small World", and parts of "Rose's Turn" and the cut "Together Wherever We Go".
Although Rosalind Russell's character is always referred to as "Mama Rose" in reviews and discussions of this film, the character is never addressed that way by anyone in the movie; the closest anyone comes is "Madame Rose".
Among the details eliminated from the musical was the fact that Gypsy Rose Lee had her teeth straightened out by a dentist owned by a gangster by the name of Waxey Gordon. The surgery may have improved her career prospects.
The trivia item below may give away important plot points.
In the original play, June elopes with Tulsa. In the film, she elopes with the otherwise unknown Jerry. While this gave Tulsa (Paul Wallace) an additional final scene with Louise, the substitution otherwise seems inexplicable.