Accordingly, once on the set in Los Angeles, Roos attended more to Affleck (his Oscar's only for writing, after all) than Paltrow. "I was all about Ben," Roos says. "It was like, 'Yeah, Gwyneth, stand over there and say your lines. Now, Ben, what do you need from me?'" Affleck dug into the role by observing real-life ad guys at TBWA/Chiat/Day and having deep discussions with Roos, himself a recovering alcoholic. "Ben is lying in practically every single scene," Roos says. "That's enormously difficult for an actor.... He asked me early on, 'Do you think I can do it?' And I said, 'I don't know that you can. I think you can.'" The result is what Affleck considers his best performance yet. "I haven't felt this way since Good Will Hunting, where I don't really care what the reception is," he says. "The movie could bomb. I'll always be proud of it."

If nothing else, it helped him smooth things over with Paltrow. "I'm not somebody who's known for having great relationships with their ex-girlfriends," Affleck says with a laugh. "I've never understood those guys. It's usually women, too, who are like, 'Of course I'm friends with all my ex-boyfriends!' How the f--- does that work? I mean, who is friends with all of their exes? Appropriately, all my exes hate me. But I realize that that was largely a mark of my own failings in the past because, though it hasn't been easy, I have been able to continue a relationship with Gwyneth that's really valuable to me."

It's also landed him in the gossip pages with alarming frequency. "Look, it's part of the deal," he says. "When I was a kid, I was reading about Sean Penn and Madonna's marriage. So I don't get too worked up." Okay, then, so how about those European snapshots that recently crossed the Atlantic? "I didn't even know that," he says. Well, whaddaya know, we just happen to have one with us!

"Not the best picture," he says, examining a photo of the pair cuddling on the Champs-Elysees. He takes a deep breath. "I was in England shooting Pearl Harbor and Gwyneth is over there doing Possession. I called her up and said, 'Let's go to Paris and you can show me around.' I saw all these French photographers hiding behind trees and stuff. She was like, 'Oh God, there's all these paparazzi people.' I just thought: Either we're going to scurry back to the hotel, or just live our lives and not worry about what people say. I do love her very much and I care about her enormously, as that picture indicates. But I hug a lot of people this way. Whether or not people believe that is up to them. I don't even know where she is right now or what she's doing." We do.

This is Leela," says Gwyneth Paltrow, introducing a lanky brunet who's just entered her trailer on the set of Neil LaBute's time-travel romance Possession at Shepperton Studios, an hour outside London. "Leela's my yoga teacher and she makes me organic, macrobiotic lunches that are delicious."

"Although today we're having pasta," Leela says.