When Olivia de Havilland agreed to make this movie, director Robert Aldrich called Bette Davis to give her the good news. He also requested she keep the news a secret until he returned in two days, when he would legally inform Joan Crawford and her lawyer by letter. However, Davis didn't listen - she called her press agent, Rupert Allan, who immediately leaked the story to the press.
Director Robert Aldrich had to take three planes, a train, and a taxi up a goat trail to get to Olivia de Havilland's house, which was in the mountains of Switzerland. It took him four days to convince her to step in and replace Joan Crawford.
Because there was no time to redo the costumes for Miriam, many of her clothes came from Olivia de Havilland's personal wardrobe. Of note is the dress (green silk chiffon) that de Havilland wears for the dinner scene with Davis and Cotten, which was from Christian Dior (by Marc Bohan) Spring/Summer 1964. The dress (including matching shoes) was sold by de Havilland's family in September 2019 (55 years since de Havilland joined the film) for $8,125.
Second movie in a row in which Olivia de Havilland stepped into a role originally announced for Joan Crawford. The other being Une femme dans une cage (1964).
When Joan Crawford was in Baton Rouge and came to film Miriam's arrival, there was no dialogue involved. Crawford was to arrive at the mansion in a cab, exit while carrying her purse, pay the driver, and, raising her sunglasses, look up at the balcony of the house where Bette Davis, in pigtails, was standing in the shadows, holding a shotgun. The scene was designed to be photographed in a wide continuous shot, and, thanks to Crawford's proficient technical skill, it was completed in one take. Later that evening, when publicist Harry Mines called on Davis in her motel bungalow, he found her standing in the middle of the room practicing Crawford's scene. "My God!", said Davis, "I've been here all evening long with a pair of dark glasses and some luggage and I'm imagining getting out of a cab and trying to do that whole business in one gesture. How did she do it?"