Director Terry Gilliam and Bruce Willis first met when casting a cast for his movie "The Fisher King." Gilliam was very impressed with a detail in Willis' Die Hard (Willis talked about his wife when he cleared the glass on his feet), and learned that it was Willis's own play during the conversation. He always remembered these and thought of Willis when he was shooting this film. Due to a tight budget, Willis, who was already a star at that time, basically played for free, just because he wanted to work with Gilliam. He didn't get the money until the film was released.
Director Gilliam made a list for Bruce Willis, telling him what to avoid in his performance, including Willis's classic "firm and melancholy eyes."
The film was inspired by the experimental short film "Dyke" made by French director Chris Mark in 1962. But Terry Gilliam hadn't watched this film before shooting.
At first, Gilliam was afraid that Brad Pitt would not be able to complete a large part of the tense and fast speech in the film, and he specially hired a speech coach for him. As a result, Pete didn't use the coach and met the director's requirements without much effort.
Brad Pitt’s pay was not high when he signed for the film. At that time, he was still on the rise. As a result, his three films "Interview with the Vampire", "Seven Deadly Sins" in 1994 and 1995 "Released one after another, making him a top star.
The idea of an army of twelve monkeys is derived from the novel "The Magic of Oz" by L. Frank Baum.
After shooting a fight scene, Bruce Willis said his line: "All I see is dead people." (All I see is dead people.)
The ending footage of the airport was taken at the Philadelphia Convention Center.
