Hollywood legend claims that, during the filming of Rock Hudson and Doris Day's bathing suit scene (set on a soundstage beach) one of Hudson's testicles kept popping out from his swimtrunks. While screening dailies the next afternoon, the crew laughed so hard, they became teary-eyed, especially when the projectionist figured how to roll the film back-and-forth so it looked like Hudson's testicle was doing a "dance."
The colors of the smoke in the explosions in Dr. Tyler's chemical laboratory correspond to the ultimate colors of the candy wrappers on the final VIP product.
About a year and a half after completing this film, its twice Oscar-nominated costume designer Irene committed suicide by jumping off the roof of Hollywood's Knickerbocker Hotel. Doris Day, in her 1975 autobiography, suggested the suicide of Irene may have been motivated by the designer's secret, unrequited love for Gary Cooper and Cooper's then recent death from cancer.
Donna Douglas was cast as Tony Randall's secretary shortly before landing the role for which she is best-remembered: Jed Clampett's daughter Ellie Mae in the long-running CBS sitcom, The Beverly Hillbillies (1962). As the screenplay was co-written by "Hillbillies" creator Paul Henning; it's a pretty safe bet he remembered her when casting the role.