Even nearly half a century since its release, The Exorcist is still one of the greatest horror films ever made, the gory and terrifying love-child of one of Hollywood's most impressive directors of the era and the maverick author of the book that the film was based on. It's one of the few horror movies to ever receive recognition at the Academy Awards and still holds numerous box office records within that genre.
Part of The Exorcist's legacy is the controversy it created when released. Infamously subject to protests, censorship, and even being banned from screening in certain areas, audiences hated and loved the film in equal measure whilst some went as far as to claim the film was outright heretical.
Production of the film was said to have been cursed. Actors were subject to some freak accidents and gruelling conditions - but mainly as a result of the director's questionable approach to making the film. From its conception through to completion, the story behind The Exorcist is every bit as interesting as the film itself.
From special effects secrets to slapping priests, here are some hidden facts about one of the most frightening films ever made.
20. Linda Blair Had Bodyguards Hired For Six Months After The Film's Release
Although only 14 years of age at the time of release there was a lot of controversy surrounding Regan actress Linda Blair's performance.
There were more than a few overtly-fanatical people that found the subject matter of The Exorcist a bit too much to handle. The film was even accused of glorifying Satan by some of the barmier religious zealots who went to see it. As a result, Blair's performance became a target for abuse and ridicule from both critics and audience goers.
But when the hate mail she received started escalating into death threats against Blair's life the studio was forced to act. Blair was assigned an armed escort for six months following the film's release until much of the hype and hate died down.