George C. Scott stars with two wives from three marriages. At the time the movie was filmed, he was near the end of his second marriage to Colleen Dewhurst. He married Trish Van Devere the next year.
Star George C. Scott fought with legendary director John Huston during the filming over script rewrites as well as the leading lady, Tina Aumont. After engaging in shouting matches with Scott, Huston quit the film. Fatefully, Aumont was replaced with Trish Van Devere, whom Scott fell in love with and married. Huston was replaced by Richard Fleischer.
In a March 22, 1971 "Time" Magazine cover story on George C. Scott, Scott was quoted on why he made this film: "I'm doing it because it reminds me of old Bogart pictures."
Harry's car is a rare 1956 BMW 503 convertible. It has an eight-cylinder engine and rather sluggish handling, unlike most BMWs. Just 139 convertibles were made from 1956 to 1959, and this may be the only one ever featured this prominently in a movie. One sold at auction in 2017 for over $580,000. In 2021 an example in good condition could be worth well over $300,000. Two of these cars were used in this film. The only other films to feature this car, but not as much, are La chasse de Saint-Hubert (1959) and L'amour est une mélodie (1956).
The trailer for the film includes a rare, candid and lengthy interview with George C. Scott, who talked about his career up to this point, as well as explaining his reaction to winning the Oscar for "Patton." This has been shown on TCM.