Here’s a frenetic concept: an ambitious Jim Carrey, at the height of his stardom in the late ‘90s, going method to play Andy Kaufman in a biopic. In 1999, the comedian went all in for his starring role in the film Man on the Moon, directed by Miloš Forman—refusing to break character even once so he could dive fully into Kaufman’s famously complex world. At the Venice Film Festival on Tuesday, Carrey admitted that the role eventually took a serious mental toll on him.

“It was psychotic at times,” he said, per The Hollywood Reporter. Carrey added that he also never broke character (well, characters—he played Kaufman and his alter ego, Tony Clifton, as well).

Carrey was discussing the film at Venice to promote a new documentary, Jim & Andy: The Great Beyond – The Story of Jim Carrey & Andy Kaufman Featuring a Very Special, Contractually Obligated Mention of Tony Clifton. The film features new footage that was shot for Man on the Moon’s electronic press kit back in the ‘90s, and shows how hard Carrey worked for the part. At Venice, Carrey mentioned that his method tendencies even spilled over into other roles. After Moon, he was set to make How the Grinch Stole Christmas with Ron Howard. However, he was so dedicated to staying in character that he once had an entire two-hour phone conversation as Kaufman while giving Howard notes on the upcoming Christmas film. Howard, bless his heart, went along with it.

"Jim Carrey didn’t exist at that time,” the comedian said. “The true author of the project is Andy and his genius, the fact that he committed so completely to what he did, really made that possible and made it essential for me to lose myself. I don’t feel like I made the film at all. I feel like Andy made the film.”

Kaufman was a deeply experimental comedian and performance artist, known for slyly blurring the lines between the real and surreal. To this day, rumors persist that his death was merely an elaborate hoax and that he’ll be making a comeback any day now—despite the fact that he actually died in 1984.

Carrey’s dedication to the role of a lifetime eventually paid off. Though the film wasn’t a box-office hit, it was praised by critics and cleaned up at awards shows. Carrey won a Golden Globe, and the film was nominated in the best-musical/comedy category.

While discussing the role, Carrey went into philosophical mode, waxing poetic about the way we all go about this world, parading as a bunch of characters.

“We spend our life running around looking for anchors. ‘Oh, I’m Italian, that’s who I am.’ The fact is you don’t exist. You’re nothing but ideas. We take all those ideas and cobble them together and make sort of a personality charm bracelet, an I.D. bracelet we wear in life. But that’s not who we are, because we’re nothing. And it’s such a fucking relief.”