Last year during the Cannes Film Festival, The Exorcist director William Friedkin revealed that he was actually invited by The Vatican to film a real-life exorcism, although that claim was vehemently denied by The Vatican. It seems that real exorcism filming was for a new documentary that he directed, The Devil and Father Amorth, which had its world premiere at the Venice Film Festival over the weekend. The filmmaker revealed in a new interview how he connected with Father Gabriele Amorth, who performs exorcisms for The Vatican's Rome Diocese. Here's what William Friedkin had to say about how he met this real-life exorcist.

"I was familiar with his books, four or five of which are translated into English. And I knew that he was kindly disposed towards The Exorcist movie, even though he had said the special effects were over the top. He felt that it helped people to understand his work. I had never tried to meet him; I never thought I could. But I was in Lucca [Italy] a year or so ago...and someone casually mentioned that Lucca was about a half-hour drive to Pisa...where there was an airport where I could catch a one-hour flight to Rome. Something clicked, and through a friend I was able to write Father Amorth. Two days later he wrote me back, and said he would meet me. This idea just popped onto my head. I call it providential. I had an inner voice that said to me, 'I wonder if I could meet Father Amorth?'"

More than 40 years later, The Exorcist still stands the test of time as what many consider to be the scariest movie ever made, which still makes headlines to this day, with a new Exorcist maze coming to Universal Studios' Halloween Horror Nights this year. The filmmaker also revealed in his interview with Variety at the Venice Film Festival that he was quite "shocked" that Father Amorth gave him access to watch a real-life exorcism, adding that he performed exorcisms every day until he got sick and passed away in September 2016. When asked about the research he conducted for this documentary, William Friedkin said Father Amorth's books are the only real research available.

"There is no research; the only research is his books. In the United States in the 20th century, there were two reported cases of possession, as far as Mr. Blatty (who wrote the novel The Exorcist) and I could tell. There were only two cases that had any substantial writing about them in the United States.The church doesn't say a lot about this. They don't try to publicize it at all. They are not promoting it. I doubt that they will even have a position about my film (this latest one). They never comment about these things. I doubt that they would have given me permission to do what I did. He gave me permission, and he operated quite independently from church procedure and was openly critical of the Vatican."

William Friedkin added that he thinks he was given this unprecedented access because, "he wanted people to be aware of his work," and that he wanted the Vatican to start training more exorcists. The director also added that he thinks he was given this access because he had the "cachet" as a well-known director to bring his story to the public through a film. Here's what the director had to say about the actual shoot, which he had to film all by himself, which involved a woman's ninth exorcist in as many months.

Related: William Peter Blatty, The Exorcist Author, Passes Away at 89

"I had to shoot it alone, obviously. The conditions were that I come along with no crew and no lights. So I used a Sony still camera that shot high-definition video. I had only that camera running and I was about two feet away from them, probably even closer. It was terrifying. I went from being afraid of what could happen to feeling a great deal of empathy with this woman's pain and suffering, which is obvious in the film. The one that I filmed was her ninth, and she was having one a month."

The director also added that he even consulted with neurologists about this unidentified woman who was having these monthly exorcisms performed on her, and couldn't tell from a scientific and a medical perspective, what was afflicting this woman. It's unclear if any of these consultations are in the film, but it certainly seems likely. Here's what the director had to say about consulting with neurologists on the film.

"I consulted with neurologists, brain surgeons, some of the best in the United States. The brain surgeons had no idea what her affliction was and none of them would recommend an operation. They believe that everything originates in the brain but - and they say this in the film - they have never seen anything quite like these symptoms....Then the psychiatrists...all described how psychiatry now recognizes demonic possession. It's called dissociative identity disorder/demonic possession. And if a patient comes in and says they are possessed by a demon or a devil, they don't tell them that they are not....They do whatever psychiatric treatment they think is necessary, including medication. And they bring an exorcist in."

William Friedkin's original movie has also spawned an Exorcist TV show, which will return for its second season on Fox starting September 29. As for the director's film The Devil and Father Amorth, LD Entertainment picked up the distribution rights to the film back in May, but there hasn't been a release date set as of yet. It remains unclear if the film will continue to hit the festival circuit as we wait for word on its theatrical release.