It is stated by Joan that she's been working on the film for 6 weeks. The film was actually shot in less than a month.
While talking with Joan Crawford about her first sexual experience. Bette Davis states "I didn't even get a tingle until I was 25. And I waited another two years before I did the deed. And that was on my God damn honeymoon".
The real Bette Davis was born in April 1908. And she married for the first time on August 18, 1932. So she was 24 when she went on her real honeymoon. Not the 27 that Susan Sarandon's Bette Davis claims.
While Bette Davis (Susan Sarandon) and her daughter B.D. (Kieran Shipka) are running lines, the soundtrack from "Charade" is playing in the background. "Charade" wasn't released until late 1963, slightly more than a year after "What Ever Happened to Baby Jane?"