Re-edited into a two part episode of "Hart to Hart" (1979) for syndication.
Guest-star Jill St. John and Robert Wagner had been friends for some time. The two married ten years later in 1990.
In his autobiography, Aaron Spelling states that Natalie Wood was the original choice for Jennifer Hart. Although she was wanted by all involved, they gave up on the idea as she was concentrating on a film career.
That's Stefanie Powers singing "You Must Have Been a Beautiful Baby" on the radio in Sam's car when he leaves the spa.
This movie was based on an old outdated script in which a husband and wife were secret agents. When it was brought back out, the spy elements were deleted and the Harts substituted for the original characters.