Ben Foster went to extreme lengths to take on the role of Lance Armstrong in Stephen Frears’ The Program, admitting just a few weeks ago that he took performance-enhancing drugs as part of his research.But speaking to the BBC at the BFI London Film Festival, where the film had its European premiere, the actor said he felt the drugs had “definitely damaged” his body, even though he took them in a “contained, doctor-supervised manner.” Foster wouldn’t name the drugs he took, except to say that they were “all legal,” or for how long he tried them. “Go faster, go longer, go stronger. That’s why you take them. And they took drugs because they work. But they also can damage the body very long-term and in very serious ways,” he said. “I had a great doctor, which helped me handle some of those consequences. But it took about half a year to get my levels right, and I would say for any athlete, you have to ask, ‘Where are your values?’ ” According to the BBC, Frears himself was unaware of Foster’s drug-taking and only found out two weeks ago. The Program, a StudioCanal/Working Title production, is set for release in the U.K. on Friday. In the U.S., it has been picked up by eOne’s Momentum Pictures and is slated for a 2016 release.