Ben Foster revealed he took performance-enhancing drugs to play Lance Armstrong in the upcoming movie "The Program," which premieres in Toronto on Sept. 13.

"I don't want to talk about the names of the drugs I took," he said, according to The Guardian. "Even discussing it feels tricky because it isn't something I'd recommend to fellow actors. 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."

Foster added that he had "only just recovered physically" from the experience. "There's a lot of fallout. Doping affects your mind. It doesn't make you feel high. There are behaviors when you've got those chemicals running through your body that serve you on the bike, but which, when you're not...."

"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," he added, according to The Hollywood Reporter.

Foster has been known for his method acting, whether it's eating dirt for a Navy Seal role in "Lone Survivor" or using glaucoma medication in his eyes to look the part of a meth addict in "Alpha Dog." He even lived on the streets before playing a homeless veteran in "Rampart." "I was pissing my pants like everyone else there," he recalled.

"The Program," directed by Stephen Frears, is an adaptation of sportswriter David Walsh's book "Seven Deadly Sins: My Pursuit of Lance Armstrong," which follows the journalist's efforts to expose Lance Armstrong's usage of performance-enhancing drugs, which ultimately led to the cyclist's being stripped of his seven Tour de France titles.