Joaquin Phoenix is opening up about his unique approach to acting.

The “Joker” star is on the cover of GQ‘s new May issue, available for free digital download, and in it he talks about the way his anxiety fuels his performances.

RELATED: Joaquin Phoenix, Rooney Mara Indulge In Plant-Based Burgers Following His Huge Oscar Win

Revealing that each new role gives him crippling anxiety and makes him physically ill, Phoenix says, “It’s pure anxiety. And I love it.”

The anxiety does mean Phoenix refuses to do rehearsals, which got him into an argument with “Joker” co-star Robert De Niro, who demanded the actor attend a read-through.

“There’s no f**king way I’m doing a read-through,” Phoenix told director Todd Phillips.

Joaquin Phoenix. Photo: Matt Holyoak for GQ
Joaquin Phoenix. Photo: Matt Holyoak for GQ

Phoenix also talks about his theory of acting, which is that what young people are taught is “completely f**king wrong,” and that acting is not about remembering lines or hitting your mark.

He says he realized this after starring in the acclaimed “Walk the Line”, saying of his performance in that film, “You just act and it’s so ugly.”

RELATED: Joaquin Phoenix Liberates Calf And Mother Cow From Slaughterhouse One Day After Winning Best Actor Oscar

The 45-year-old also looks back on a defining moment in his life, after shooting “Walk the Line”, when he was drinking heavily and going to clubs.

“But I wasn’t engaging with the world or myself in the way I wanted to,” he admits. “I was being an idiot, running around, drinking, trying to screw people, going to stupid clubs.”

During this period, Phoenix got into a bad car accident and was rescued from the vehicle by German director Werner Herzog. After that experience he stopped drinking and smoking weed.

“There’s too many things I enjoy doing and I don’t want to wake up feeling hungover. It’s not a thing I fight against – it’s just the way I live my life,” he says.

Read the full feature in the May issue of GQ, available via free digital download and on newsstands from today.