By Kevin P. Sullivan
Updated September 11, 2015 at 04:42 PM EDT

There’s method acting, and then there’s Method Acting.

Ben Foster has once again dabbled in the latter for Stephen Frear’s upcoming Lance Armstrong biopic, The Program. In an interview with The Guardian, Foster — who previously lived on the streets for Rampart and ate dirt for Lone Survivor — revealed that he took unspecified performance-enhancing drugs to get into the mindset of the disgraced cyclist.

“Doping affects your mind. It doesn’t make you feel high,” Foster said. “I’ve only just recovered physically. I’m only now getting my levels back…. I don’t know how to separate the chemical influence from the psychological attachment I had to the character. If it’s working, it keeps you up at night. This is losing your marbles, right? They’re definitely rolling around. They’re under the couch but they’re retrievable.”

According to a rep for Foster, the actor used the drugs under the supervision of doctors, and in The Guardian story, he discourages others from following in his footsteps. “I don’t want to talk about the names of the drugs I took. Even discussing it feels tricky because it isn’t something I’d recommend to fellow actors,” he said. “These are very serious chemicals and they affect your body in real ways. For my own investigation it was important for me privately to understand it. And they work.”

The Program is set to have its world premiere Sunday at the Toronto International Film Festival. There’s currently no U.S. release date scheduled.

WATCH: EW News Flash live from TIFF 2015.

The Program

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