Clint Eastwood has directed and starred in several films, but he only worked with Kevin Costner on a 1993 thriller because the younger actor rewrote the script. Both Clint Eastwood and Kevin Costner are legends of the Western genre, both in front of and behind the camera. Eastwood's best Westerns include legendary films like the Dollars trilogy and Unforgiven, and he's also directed hits like Million Dollar Baby and Gran Torino. Likewise, Costner has had his fair share of major acting hits like Field of Dreams and JFK, as well as massively successful directorial outings like Dances with Wolves.

Despite their success, Eastwood and Costner only ever appeared in one film together, and it wasn't even a traditional Western. 1993's A Perfect World was a crime thriller about an escaped convict who kidnapped a young boy, and it pitted Costner and Eastwood on opposite sides of the law. What's more interesting than the film's genre,...