The Exorcist is one of the greatest horror movies classics. With nearly five decades, the production has influenced — and still influences — generations of filmmakers in the genre, either by the terrifying story or the techniques used in the production that help create the perfect setting for the film.
One of the techniques used by the director, William Friedkin, was not to tell the cast about some of the things that were going to happen, in order to register their true expressions during the recordings. The method — much criticized and now rejected by Friedkin himself — had its most striking consequence in the scene where young Regan MacNeil (Linda Blair) vomits in the face of Father Damien Karras (Jason Miller).
During an interview with film critic Mark Kermode for the BBC documentary The Fear of God: 25 Years of The Exorcist, Miller commented that he didn’t expect this to happen. According to the actor, the plan was for the vomit to reach his chest — as it did during rehearsals. However, to everyone’s surprise, when the cameras were recording, the vomit (pea soup was used in the film) was suddenly directed at her face.
However, this wasn’t the only unexpected incident on the set of The Exorcist. Among the director’s unorthodox methods of eliciting “spontaneous” reactions from his actors, Friedkin also had shotguns firing on set to create tension. The idea was for the actors to be tense and uncomfortable with the gunfire.
Another well-known behind-the-scenes story involves Friedkin slapping a real priest before a scene to provoke an emotional response and put it in the movie. The case happened to Father William O’Malley, who played Father Joseph Dyer in the film. Friedkin would have asked O’Malley, “Do you trust me?” before giving the slap.
Since then, Friedkin has sometimes said that he regrets some of his filmmaking techniques and that he would not employ them today. The Exorcist hit theaters in December 1973 in the US. The film also won the Oscar for best adapted screenplay.