"The Exorcist" director William Friedkin is releasing the documentary "The Devil and Father Amorth" this April.

The movie delves into an actual exorcism that Vatican exorcist priest, Father Gabriele Amorth, conducted a few months before his death - but unlike his famous movie "The Exorcist," this documentary will be sans the makeup and Hollywood special effects.

Friedkin witnessed Father Amorth at work when he got a personal invite to join him in one session in May 2016. The director told Variety that he had personally met the priest who then allowed him to film without any crew, so he took the video himself.

"It was terrifying," the director admitted in witnessing exorcism first-hand. "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."

Father Amorth had been exorcising this woman as he said she was suffering from "demonic possessions". Friedkin said that when he showed the video to neurologists and brain experts, they mostly could not believe it but they also added that they wouldn't recommend brain surgery as a way of treating her ailment. Friedkin also showed the video to psychiatrists.

"Psychiatry now recognizes demonic possession," the director said. "It's called dissociative identity disorder/demonic possession."

The documentary comes as Vatican recently announced plans to train new priests to become experts in exorcism due to a rising demand in Italy. Father Benigno Palilla, another trained exorcist, confirmed that the course would take place in April at Rome's Pontifical Athenaeum Regina Apostolorum in Rome.

Exorcism is in the Code of Canon Law but the Catholic Church approves its execution only after following a chain of command involving senior priests.

Meanwhile, Father Amorth died on September 2016 at the age of 91. In 2013, he claimed to have done over 160,000 exorcism in his time as a priest, although some of these cases didn't actually involve driving demonic possessions out of someone's body but rather offering ritual prayers.