For years, John Saxon said he had been bothered by something about Sandra Dee during filming that he just couldn't put his finger on. Decades later he figured out what it was: Sandra's mother had lied about her age to get her more adult roles. Sandra was only 14 years old at the time of filming.
The film was shot in Paris because Rex Harrison was having tax problems and could not go to the U.S. or the U.K.
This was the only film that Rex Harrison and Kay Kendall made together during their marriage. Kendall died from cancer the following year at the age of 33.
Because there was a musicians' strike at the time this movie went into post-production, only recycled source music is heard in the ball sequences, while the main title theme was lifted verbatim from the soundtrack of another Vincente Minnelli comedy, Designing Woman (1957).
At the first ball, the song to which Jane (Sandra Dee) is dancing is "The Boy Next Door". The song is from Meet Me in St. Louis (1944), also directed by Vincente Minnelli.