The identity of the actress Celeste Holm who did the voice-over for Addie Ross was kept secret when the film was released. The studio held a number of "Who is Addie?" contests around the country where moviegoers could guess the actress' name.
Joseph L. Mankiewicz had a real battle with the American censors at the time who would not permit him to use words like "laxative" and "toilet" in his script. He got his revenge with a famous double-entendre laden exchange which used words like "penetration" and "saturation".
At one point the film was called "A Letter to Four Wives". Upon submitting the adapted screenplay to 20th Century-Fox chief Darryl F. Zanuck, Joseph L. Mankiewicz mentioned that he found it too long and asked how he felt the movie could be shortened. "Take out one of the wives," Zanuck replied. Originally, the movie would have featured Anne Baxter as the fourth wife. Zanuck didn't feel Baxter's segment was as strong as the other three, so that one was cut.
Celeste Holm was initially not remotely interested in providing the off-screen voice of the letter-writer and was more inclined to take the part that eventually went to Ann Sothern. Joseph L. Mankiewicz persuaded her that her involvement would be absolutely crucial to the film's success.
Linda Darnell and Joseph L. Mankiewicz became romantically involved during the making of the film. Darnell considered Mankiewicz to be the great love of her life but he refused to leave his wife. He later remarked that she was "a marvelous girl with terrifying personal problems".
Linda Darnell's home which shakes when the train passes by was inspired by Joseph L. Mankiewicz's childhood home in New York City. His father would always stop talking as he waited for the Third Avenue El to pass by.
Melville Baker and Dorothy Bennett wrote the first treatments of the script. Even though he was not credited for the final film, it was Baker who had the idea that the character Addie was only to be heard, and not seen.
Based on the novel by John Klempner. In the novel, Lora Mae is less a gold digger than a woman who has always been dominated by her wealthy husband; Rita is trying to succeed in a second marriage with a man she has never felt passionate about; and Deborah is a plain and quiet ex-spinster whose "catch" of a husband has been disappointed in her lack of success in society.
Shortly after filming A Letter to Three Wives, Sothern contracted infectious hepatitis after getting an impure serum shot while she was in England for a stage performance. She was confined to her bed where she continued to work on the Maisie radio program while she recuperated. Sothern later said that her illness had restored her faith.
In the novel, there are five, not three wives. Two wives were eventually cut from the movie.Martha (Anne Baxter's character) and her husband locked horns over child-rearing issues while Geraldine (fifth wife) was devoting excessive time and money to her singing career with few results.