At 23-years-old, the richest and most famous child actor ever is all grown up. Party Monster is the on-screen return of the Mack after a nine-year hiatus, since Richie Rich in 1994. Based on New York underground club icons Michael Alig (Culkin) and James St James (Seth Green), Party Monster is Culkin as you've never seen him before - as his camp and elegantly wasted character spirals towards his twisted destiny...

Did you take time off from acting in order to stop being a Hollywood commodity?

Exactly. It's weird when people say [about Party Monster], "Oh you did this to get away from the work you did before." Well, that implies I'm trying to break out of some kind of box that I've been put into. The reason I took so much time off is I felt the industry defined me, and I wanted to define myself. So I had to take back my own life, and I had to go away for eight years. I was losing touch with my family and I hadn't done a full year of schoolwork in my entire life, so I had to take control of myself again.

Was the whole club scene alien to you? Being a New Yorker, were you aware of the Club Kids and the Limelight?

I was aware of the Limelight Club. I wasn't aware of Michael Alig and James St James - they were going on when I was 12/13-years-old. I'd never been to a club until I was 20-years-old - in London, which is a great place to start going to clubs. I did the rounds - China White, Fabric, and Soho House. I was a member of a couple of private clubs and stuff like that. The drugs and all that stuff were all new. I never did K before, or any of those things.

How was the experience of meeting Michael Alig in prison?

Michael left us waiting for two hours, he's still fashionably late, even when he's in prison. It was Michael being Michael. Then we spoke for three hours. When Seth [Green] met James St James, he had a list of questions, but I didn't want to do that with Michael. I think everything that had happened in Michael's life was leading up to somebody making a movie about it. I figured I'd like him to do all the talking and tell me all the things he wants me to know about himself - I wasn't going to just pound him with questions.

So how is your return to acting working out, compared to your experiences when you were much younger?

Before, I was doing things that I didn't really want to, and I lost the joy, because it became like a machine. I was being forced to do something I didn't want to do. But when I look back on it, I did truly enjoy doing it. It was just a matter of finding the joy again, and I think I have.