When Billy Wilder and Charles Brackett turned in their script, the studio liked it but felt it needed some work. The writers they hired to rewrite the script were ... Billy Wilder and Charles Brackett. The studio sent them their own script to rewrite without knowing it. Wilder and Brackett simply retyped their original script and the studio loved the "rewrites" so much, they produced it with no further changes.
After Wilder and Brackett fought with director Mitchell Leisen to make sure as much of their work made on the screen as possible, Wilder was convinced he had to direct the scripts they wrote and Brackett was convinced he had to produce.
Barbara Stanwyck originally was slated for the role of Eve Peabody, but she was replaced by Claudette Colbert because of scheduling problems.
When John Barrymore was cast, it was well known that his alcoholism would necessitate some accommodation. This accounted for the presence in the cast of his young wife, Elaine Barrie. When he could not remember some of his lines, they were written out on blackboards just off camera, and both his irascibility and sense of humor were in evidence. At one point, one of the female assistants on the set went into the ladies room, only to be confronted with the sight of Barrymore, his back turned, relieving himself. "You can't be here," she protested, "it's just for ladies." He turned around and retorted, "So's this!" This incident was turned into a gag by Peter O'Toole in L'ospite d'onore (1982), whose retort in the same situation was, "So is this, madam, but first I must run a little water through it."
Mary Astor's pregnancy caused some filming problems. Many of the camouflage film angles, as well as cleverly draped fashions, are still in use over 80 years later, as pregnant actresses still present unique filming opportunities.