The producers considered replacing Tallulah Bankhead during filming after she became ill and was unable to work. However, Bankhead put up her salary for the film as a guarantee.
A rivalry between Tallulah Bankhead and Stefanie Powers was fabricated by the press to boost interest in the movie. In real life they got along well and their friendship continued after filming wrapped.
There was a problem with the audio when Tallulah Bankhead uttered the infamous line, "You must die! Die, my darling," so Bankhead later had to loop the dialogue. She arrived inebriated at a New York recording studio four hours late, and it took her the rest of the day to properly dub the line.
The subplot concerning Mrs. Trefoile's past as an actress was not part of Richard Matheson's screenplay. The director added it after Tallulah Bankhead was cast, and she was initially furious that the set included photos of her younger self.