Final theatrical movie of Beatrice Lillie (Mrs. Meers). She was showing early signs of Alzheimer's disease, and had trouble memorizing her lines. During filming, Dame Julie Andrews stood off-camera and repeated Lillie's lines to her, so Lillie could complete her scenes.
Mary Tyler Moore said that she always thinks of the tap dancing scene in this film whenever she sees an elevator.
According to Mary Tyler Moore's autobiography "After All", Lew Wasserman had brought her to Universal Pictures after her unexpected success as a comic actress on The Dick Van Dyke Show (1961) with the hopes of making her "the next Doris Day" in light movie comedies. Moore contends that this film was intended as a light comedy rather than a musical, but that its focus shifted with the signing of Julie Andrews flush with the success of The Sound of Music (1965) whose character became the film's focal role with Moore's role becoming secondary. Moore's assertion is at variance with 1966 press reports indicating Andrews being attached to this film prior to Moore: also director George Roy Hill would state that he was given the film's script by Andrews (whom he'd directed in Hawaii (1966)). Ostensibly, Andrews had been given the script because she'd starred in the Broadway "Roaring Twenties" musical ''The Boy Friend''. Hill would also state that Moore reluctantly accepted the role of Miss Dorothy, feeling she was being miscast.
In his autobiography ''The Stage Struck Me'', Neville Phillips noted the similarity between the plot of this film and ''Chrysanthemum'', a short-lived 1956 West End musical whose book Phillips co-wrote. Regarding his lack of legal response, Phillips opined: "What chance would an almost penniless British writer have against the might of 20th Century-Fox" - mis-identifying the studio which produced the film - "who I am sure would be able to persuade a jury that the similarities were purely coincidental. [But] personally I don't believe they were."
Carol Channing was the first name producer Ross Hunter had mentioned when he began planning this movie, Hunter saying of Channing: "She was born and still lives in" the Roaring Twenties, adding that Channing would be "as big in movies as on the stage." However Channing's availability was for some time problematic due to her commitment to the Broadway musical ''Hello, Dolly''. Eventually Channing was able to negotiate a leave of absence from Broadway, agreeing to give her contracted "Hello, Dolly" tenure an extension equivalent in length to that required for her secondment for this film. Channing was eager to make the film: she hoped to reprise her Broadway role in the upcoming film version of Hello, Dolly! (1969) and, having made virtually no big screen appearances, wanted to have the cachet of being in the hit musical this film promised to be. Despite earning Channing an Oscar nomination, this film would ironically put her out of contention for Hello, Dolly! (1969) Its producer, Ernest Lehman, had been keen to have Channing reprise her stage role until he saw her as Muzzy, since he felt that Channing came across onscreen as "cartoonish."