Premise: Spaceballs is a 1987 American comic science fiction film co-written, produced and directed by Mel Brooks. Starring Brooks, Bill Pullman, John Candy, and Rick Moranis, the film also features Daphne Zuniga, Dick Van Patten, and the voice of Joan Rivers. In addition to Brooks in a supporting role, the film also features Brooks regulars Dom DeLuise and Rudy De Luca in cameo appearances.
Hypothesis: Dom DeLuise and Rick Moranis were supporting actors in film, whereas Rudy De Luca was one of the starring actors.