Dudley Moore adopted the moniker Stanley Moon in this film after John Gielgud wrote him a letter of introduction because he was impressed with Moore's work in the stage revue "Beyond the Fringe". Gielgud obliviously referred to Moore as Stanley Moon in the letter, and an amused Moore adopted the name as an alter ego for the rest of his life. After they worked on Arthur (1981) and Arthur 2: On the Rocks (1988) together, Gielgud good-naturedly said that he "got to know Stanley Moon rather well."
An article about Peter Cook that appeared in the New Yorker stated that the filmmakers didn't have a title for Bedazzled (1967) when it was being made. Cook suggested calling the film Raquel Welch. The producers didn't understand why Cook would want to name the movie after an actress that only appears for a few minutes in it. Cook explained that movie marquees put the lead actors names over the movie title. Thus the letters on the marquee would say "Peter Cook and Dudley Moore in Raquel Welch". The producers ended going for the more ordinary title.