Making this movie was the first time Ingrid Bergman had been on a Hollywood sound stage since the 1940s--all her subsequent films up to that point had been made in Europe, even those for American studios.
The play had been a comeback vehicle for Lauren Bacall following several years of inactivity once screen roles dried up. "Cactus Flower" was an enormous hit on Broadway, and Bacall garnered strong personal notices for her performance as Stephanie, playing the role for nearly two years. She was understandably disappointed when producer M.J. Frankovich cast Ingrid Bergman in the film version.
Tuesday Weld turned down the role of Toni Simmons, which earned Goldie Hawn an Oscar for Best Supporting Actress.
The original Broadway production of "Cactus Flower" by Abe Burrows opened at the Royale Theater on December 8, 1965, and ran for 1234 performances starring Lauren Bacall and Barry Nelson.
The three kids seen behind the GTO in the GM 5th Avenue showroom during Walter Matthau and Goldie Hawn's NY walkabout are David Matthau and Jenny Matthau and I.A.L. Diamond's son Paul Diamond