Anthony Perkins and Stephen Sondheim used to host murder mystery parlor games in Manhattan, New York during the late 1960s and early 1970s. The pair put on these occasional ruses for their friends, such as Lee Remick and George Segal. Another of their guests was producer and director Herbert Ross, who encouraged them to write a script based on this type of party.
From working on this movie, James Mason famously once said that Raquel Welch was "the most selfish, ill-mannered, inconsiderate actress that I have ever had the displeasure of working with."
Christine (Dyan Cannon) was based on Hollywood mega-agent Sue Mengers, who was Cannon's agent at the time. It has long been part of the behind-the-scenes lore that Mengers was originally offered the part, but she declined (claiming she couldn't act) and recommended Cannon for the part (Richard Benjamin had also been a previous client of Mengers). However, during a January 26, 2020, American Cinematheque Q&A session with Benjamin and Cannon, Cannon debunked this rumor, saying that while Mengers was the inspiration for the role, she had never been considered to play it.
The production was marred by much on-set conflict. This has been attributed to delays, weather, sea-sickness, personality clashes, over-crowding on the boat and the alleged prima donna antics of Raquel Welch. Reportedly, props were thrown across the set.
Filming the café scene was disrupted when the group known as "Black September" informed police that a bomb had been placed near the set and would be detonated unless everyone left. With help from the local police, the actors, actresses, and crew carried on bravely and finished shooting on schedule at 3 a.m. Raquel Welch was quoted saying, "I was glad when we finished, and that the threat seems to have been a hoax."