04/10/2006 at 01:00 AM EDT
Fans were calling Hartnett "Hotnett" even before his breakout turn in 2001's Pearl Harbor
. These days the Minnesota native, 27, is seeking out quirkier roles: an average Joe targeted by Mob bosses in Slevin
and a 1940s cop in the upcoming Black Dahlia
. (He recently shrugged off questions about a romance with Dahlia
costar Scarlett Johansson
: "There's always a rumor.") He chatted with Natasha Stoynoff.
Shooting Slevin, you spent two weeks wearing only a towel.
"Everyone was very respectful of my towel space. There were towels that looked more manly, but I liked that it was violet and had little flowers on it."
What qualities do you look for in a woman?
"I look for someone who has a big personality and a lot of confidence. And on top of that, women [who] I think are incredibly beautiful. Usually they're just a little bit different than everybody else. Trying to get to know a woman is what life is all about."
You're vegetarian. How did you manage while shooting Black Dahlia
"It's all meat, all the time, over there. I was trying for a while, but I would work 12 hours and then box four hours every night. I was gaunt. The doctor told me, 'Eat meat.' And that was it."
How was acting with Scarlett Johansson
"She's great to work with. Scarlett has an almost improvisational kind of feel. Everything affects her. She's very real."
You play an ex-boxer in Dahlia
. Did your other costar Hilary Swank have any tips?
"She did offer to get in the ring with me. She'd been training for so long, I thought maybe it wasn't such a good idea."