Brad Pitt, star of the forthcoming sword-and-sandals blockbuster Troy, says it's almost time for him – and his wife Jennifer Aniston – to give way to a new generation of stars. He talks to John Hiscock.

He certainly doesn't look it, but Brad Pitt considers himself an old man in film-star years. With his 40th birthday looming, he has, he estimates, another four years to make films, sign autographs and dodge the paparazzi before focusing on other things that are claiming his attention, such as devoting more time to his hobby of architecture and starting a family with his wife, the former Friends actress Jennifer Aniston.

"There's a new generation coming up and we need new voices in the industry," he says, sounding like the veteran he sees himself as.

"We figure that anything we want to do, film-wise, we have to get out of our systems before kids come along because they are going to be the priority and we won't be able to do everything we want to do then."

Considering he was coming to the end of a weekend of interviews, television shows and photo sessions, Pitt was in a relaxed and outgoing mood when we met in New York. Outside his hotel, dozens of fans blocked the pavement hoping for a glimpse of him, but if they had seen him slipping in unobtrusively through a back door they probably would not have recognised him.

Dressed in a blue shirt and scruffy pair of jeans with holes at the knees and with his once long blond hair cropped almost to his skull, he looked more like an off-duty kitchen porter than the star of one of the most expensive films ever made and one that is expected to rule the box office this summer.
Only the heavily muscular arms and sculpted physique hint that for eight long months of filming in Malta, Mexico and London, he was Achilles, the warrior whose heroics lead the Greek forces to triumph in director Wolfgang Petersen's £150 million sword-and-sandals epic Troy.

It could well emerge as the role for which he will be remembered above all others. As Achilles, he commands the screen and displays a force and power that he has never shown before, despite some clichéd and uninspired dialogue.

Petersen says of him: "This could be the role of his life. Because Achilles was like a pop star, it made complete sense to cast a god-like creature like Brad Pitt to play him."

Although Petersen was familiar with Pitt's heartthrob reputation, he was unprepared for the scenes that greeted them whenever they went out in Malta, where much of Troy was filmed.

"It was absolutely crazy," he recalls. "It was like the Beatles were there. When we came out of a fish restaurant one night there were hundreds of people screaming and pushing, trying to get near him. When we were filming, we had to shake the nearby trees to get rid of the people who were hiding up them to get a glimpse of him.

I said to Orlando Bloom [who plays Paris], who nobody had ever heard of then, ‘Prepare yourself because one day this could happen to you, too.'"

While Petersen has nothing but fulsome praise for Pitt's dedication and ability, he had to adjust to Pitt's 21st-century acting style. One of the emotional high spots of the film is a powerful scene between Pitt and Peter O'Toole, who could be in line for an Oscar nomination for his performance as the tragic Priam, the King of Troy. For Petersen, it highlighted the difference in the two men's acting styles.

"Peter O'Toole needs very little direction," he said. "He comes prepared, he knows what he wants to do and he does it. We needed very few takes. He's old school. Brad is very different. He likes to try doing things in a lot of different ways. He likes to improvise and is very innovative. We needed many takes."

Mention O'Toole to Pitt and his eyes light up. "I can't say enough about the man," he enthuses. "He's a force of nature. I was supposed to meet him for a little cocktail and I got there at four in the afternoon and left at 4am. I couldn't take it any more and he was still holding court. He's a professional."

To play Achilles, Pitt dedicated himself to getting into shape. For six months before filming began and during the six-month shoot he trained daily, dieting, working out and – except when he was with O'Toole – going to bed early.

"I figured, ‘What the hell? I'm going to be 40, everything's falling apart so let's see what I can do.' I did everything by the book, did everything the trainers said, and it hurt. It was a lot of work and I was really disciplined about it."

He even stopped smoking, although he admits that he has started again, sheepishly producing a packet of Marlboro and saying: "But I'll quit again soon."

Pitt appears to be one of the few of today's established stars who has little interest in his public profile. He seems embarrassed by the looks bestowed on him by genetic good fortune.

Steven Soderbergh, his Ocean's 11 and Ocean's 12 director, says of him: "He's a very secure person. He would be exactly the same person whether stardom had happened to him or not. He is just who he is."

Pitt grew up in the small town of Springfield, Missouri, and attended the University of Missouri where he gained a degree in journalism, which has tended to make him slightly more tolerant of the fourth estate than some of his fellow celebrities. He set his sights on a career in advertising but felt the lure of Hollywood.

So, telling his parents he was going to attend an art college in Pasadena, he loaded up his car and headed west to California. He studied acting while working at odd jobs, including driving strip-a-gram girls around the city, dressing up in a chicken costume to promote a fast food restaurant and delivering refrigerators.

He landed small roles in daytime soap operas, appeared in three episodes of Dallas and entered feature films through the well-travelled road of supporting roles in slasher films and teen sex comedies. His breakthrough came as the hitch-hiking charmer who seduces Geena Davis and then steals her money in 1991's Thelma and Louise.
Instead of taking the Tom Cruise route and cashing in on his instant stardom and good looks, Pitt opted for smaller, more varied roles which offered personal satisfaction rather than career momentum. He played the troubled younger brother in Robert Redford's A River Runs Through It, the stoner room-mate in the Quentin Tarantino-scripted True Romance, an arrogant cop in Seven and the twitching mental patient in the Terry Gilliam-directed 12 Monkeys.

He co-starred twice with Anthony Hopkins, in Legends of the Fall and Meet Joe Black, and took a turn as an Irish gipsy in Guy Ritchie's Snatch.

Troy is his first film since Ocean's 11 two and a half years ago, but he has not been idle. A keen student of architecture, he has been designing and building a home and studio in the Hollywood Hills, where he and his wife hide from the public gaze and indulge themselves in their hobbies of architectural design and photography (Pitt) and painting and sculpting (Aniston).

Pitt's fondness for architecture has led to him join Frank Gehry on a committee formed to plan the development of land next to the Disney Concert Hall in downtown Los Angeles. But at the moment, work takes precedence. He has just finished filming Mr and Mrs Smith with Angelina Jolie and has started work on Ocean's 12.

Now that Aniston is no longer tied to the daily grind of Friends, she will be visiting him on location.

"It's a great time for Jen," he says. "It's very interesting because a transition is under way. There's the melancholy of saying goodbye to an era which was very important to her and gave her some amazing experiences, and now there's the excitement of the unknown. What's the next era going to be? She's right in the middle so there's a real pleasure and pain to all of this."

Could the next era involve children?

"A family? No question," he says firmly. "We're heading that way. It's a natural progression for us, and it's time."