Actor Bradley Cooper, 37, hasn't just pretended to have a "Hangover" - he suffered from plenty of them until he became sober at the age of 29.
Cooper opened up about his struggle with addiction to the Hollywood Reporter.
"I don't drink or do drugs at all anymore," Cooper told the magazine. "Being sober helps a great deal."
Although the "Hit and Run" actor lives a relatively tame lifestyle now, his life was out of control during his twenties.
"I was at a party and deliberately bashed my head on the concrete floor -- like, 'Hey, look how tough I am!' And I came up, and blood dripped down. And then I did it again," he admitted. "I spent the night at St. Vincent's Hospital with a sock of ice, waiting for them to stitch me up."
Cooper's addiction stemmed from insecurity; the star was not comfortable in his own skin until he became an actor.
"I was so concerned what you thought of me, how I was coming across, how I would survive the day. I always felt like an outsider. I just lived in my head," he said. "I realized I wasn't going to live up to my potential, and that scared the hell out of me. I thought, 'Wow, I'm actually gonna ruin my life; I'm really gonna ruin it.' "
Friends were worried about his behavior, but Cooper had to realize his problems and change them on his own.
"Part of me believed it, and part of me didn't. But the proof was in the pudding: I'd always gotten up at the crack of dawn, and that was out the window. I remember looking at my life, my apartment, my dogs, and I thought, 'What's happening?' "