Fire, Death & A Curse: The True Story Behind 'The Exorcist'

Terrifying and groundbreaking in equal measures, director William Friedkin's 1973 classic The Exorcist coupled what were extravagant special effects for its time with the feeling of a pared-down production to create a stunningly disturbing film that influenced dozens of horror hits in the years that followed.

Starring 13-year-old Linda Blair as the demonically possessed Regan MacNeil, the film became an instant box-office hit — despite outrage from religious groups who believed it glorified Satan. Televangelist Billy Graham even blasted, "There is a power of evil in the film, in the fabric of the film itself."

Here, RadarOnline.com reveals some of the long-hidden secrets behind one of the scariest movies ever made.

"The Exorcist," and the 1971 novel of the same name on which the film was based, was inspired by a true story: the 1949 exorcism of a young boy known by the pseudonym Ronald Doe. At the time, future novelist William Peter Blatty was a student at Georgetown University, which is why he set his story in Washington, D.C., near the college's campus.

Friedkin never thought he was making a frightening film. "I know that it is considered by a great many people as a horror film," he says. "I've never thought of it that way and I didn't approach it that way. It's a story about the mystery of faith."

Linda was chosen for the part of 12-year-old Regan from nearly 600 girls, but she wasn't sent by an agent to audition — she was brought to the Warner Bros. casting department by her mom!

Oscar-winning star Mercedes McCambridge was tapped to dub Pazuzu's dialogue. Mercedes, who won the Best Supporting Actress statue for her work in 1949's "All the King's Men," had once been called "the world's greatest living radio actress" by the legendary Orson Welles.

To roughen her voice for the role, Mercedes insisted on swallowing raw eggs, chain smoking and drinking whiskey — despite being a recovering alcoholic. Friedkin also arranged to have the actress bound to a chair during takes, so her voice would more accurately reflect that of the struggling demon.

During the exorcism scenes — in which a priest tries to expel the demon from Regan's body — the bedroom set was refrigerated to capture the foggy breath of the actors. Linda, who was clad in a thin nightgown during filming, says to this day she cannot stand being cold.

A series of strange occurrences during and after filming led some people to believe the set and movie were cursed.

At one point, shooting was delayed after the set for the MacNeil home caught fire. The blaze was blamed on a pigeon that found its way into a circuit box, but eerily, Regan's bedroom survived without any damage. Ellen Burstyn — who played Regan's struggling but devoted single mother, Chris — was injured during a scene in which the possessed child threw her to the floor — and the take was actually used in the film. Ellen's blood-curdling scream was real!