Elias Koteas improvised much of his lines and actions. When Duncan puts his head on Amanda's shoulder, Lea Thompson's surprised laugh was real.
Howard Deutch and Lea Thompson fell in love while filming this film, have been married since 1989, and are the parents of actresses Madelyn Deutch and Zoey Deutch.
The car that Watts drives in the movie is a dilapidated Mini Cooper, modified for driving in America. Between 1960 and 1967, only 10,000 were sold in the U.S., and then discontinued. Although they are very popular now, they were quite alien and unknown to most of the American public in 1987.
Molly Ringwald was offered the role of Amanda Jones, but refused it, ending her successful relationship with John Hughes.