Moviegoers hungry for more will find the paradoxes of human nature at work in Total Eclipse, which examines the nihilistic love affair between the French poet Arthur Rimbaud (played by Leonardo DiCaprio) and his mentor Paul Verlaine, a man whom Thewlis describes as "very promiscuous, complicated, confused and brutal". And balding, which accounts for Thewlis's shining pate where once was golden hair. Pulling off his cap at the Musee d'Orsay, he publicly exposes his partially shaved head - a moon in a hair hula skirt. He stands before the images of Rimbaud and Verlaine in Fantin-Latour's "Le Coin De Table" and strikes the pose of his alter ego. For a moment Thewlis seems to have sprung from the painting.

The movie, scripted by Christopher Hampton (Dangerous Liasions) from his own play, was originally set to star River Phoenix as Rimbaud and John Malkovich as Verlaine. When Phoenix died, the part fell to DiCaprio. "And when he accepted, Malkovich ran out of reasons that are complicated," says Polish director Agnieszka Holland. Refusing to elaborate, she moves on: "The first idea that came into my head was David. I had seen him in Naked and I needed someone very different."

"When Agnieszka said, 'We have this guy, David Thewlis,' I was, like, Oh my god," enthuses young DiCaprio. "Me and all my friends are huge fans of that movie.

"He's the most unpretentious English person I've ever worked with," adds the 22-year-old, who then confesses he's never worked with another English actor. But even so: "He's just one of those eternally cool guys."

How apropos to cab it to a district where men are strolling down the street hand in hand. Asked if he had any reservations about the homosexual love scenes in the film, Thewlis - who is heterosexual - smiles wryly. "Certainly if anyone was worried about doing it, then that would call their sexuality into question more than if they did it. It's like, What are you scared of? That you might like it? So what if you do?"

Entering the Foufounes, a restaurant in the Marais district, one is greeted by the Village People singing "YMCA" over the sound system. Thewlis orders a carafe of red wine and continues. "Leo was a little uptight about the homosexuality in the film." He grins, lights a cigarette. "He coped with that by being Beavid and Butt-head about it."

"David is just matter-of-fact," says Holland. "He helped Leonardo to do things that were much more difficult for Leonardo. When you are 20, to do this kind of stuff is very risky."

So the two went about the business with a sense of humour. "There was a sequence of me being sodomised by Leonardo," Thewlis recalls. "When we filmed that, it was hysterical. I'm lying face down on the bed naked, Leo's behind me with a cushion between us, and I'm screaming my head off. I don't know, it was just fun!"

"I wasn't exactly nervous about it," admits DiCaprio, "but I was a little quesy. But it was cool...just the fact that David...he was right there for me..." A pause. "He was just very honest and he didn't...aw shit, I don't know what I'm saying."

According to Holland, the atmosphere on the set "was one of the most joyful I've ever had," and yet, by the end of the filming, she saw that Thewlis "was so much in the character, he became this incredibly violent and unhappy gay poet. Week to week he was more homosexual in some way. He wanted to escape from that and to find his girlfriend again. And to become David Thewlis, not Paul Verlaine."