Elmer Bernstein, the film's composer, has an unaccredited role as a member of a jazz band called The Red Peppers. Bernstein is the man in the red shirt who wears sunglasses.
This the next-to-last feature film appearance of veteran character actor Jack Oakie, who plays Mac, the owner of Mac's Bar. Oakie's last film appearance was in the Doris Day/Rock Hudson comedy Ein Pyjama für zwei (1961) one year later in 1961. Oakie went on to make TV appearances until 1966. He passed away on January 23, 1978 in Los Angeles, California.
Tony Curtis and Debbie Reynolds appeared in three movies together: "The Rat Race" (1960), "Pepe" (1960) and "Goodbye Charlie" (1964).