Brad Pitt, one of the all-time hearth-throbs, is happy to hand the baton to a new wave of leading men and focus on lifting his own game.

Brad Pitt turns 40 this year. It is hard to believe the resident spunk trunk to at least two generations of female cinema audiences is officially middle-aged, but there you go: the years tick by for king and pauper alike. Mind you, Pitt’s 40 doesn’t look much like yours or mine. The perfect chin is firm, the brow as smooth as a teenager’s, the laugh lines vestigial. That boyish charm is good for a while yet.

And right now, Pitt is groomed for Achilles, his starring role in Wolfgang Petersen’s film, Troy, now filing in Malta, which has required him to grow his surferblond hair to his shoulders and spend a lot of time in the gym. Looking at him, I’d say there’s not much wrong with any of this; the one disappointment is that the Greek fought on foot rather than on horseback. Remember Legends of the Fall? Not the best film of all time admittedly, but Pitt looks very, very good on a horse.

Ah yes, 40. A couple years ago, Pitt says in that breezy, lazy voice that places him exactly midway between his Missouri truckin’ past and Californian dude present, he and his wife, Jennifer Aniston, were arguing about how old he was. This is hard to believe, but he said it. “I thought I was older than I was; I had already missed a year,” he says. “We had to call my mum because even with math and knowing the year I was born, I could not figure it out.”

Which makes him relaxed about the 40 landmark, because in his head he’s already there. “Certainly it’s not like when I saw my mum go four-oh and I’m like damn! You’re old! But you don’t feel any older, do you?” Except for the wisdom, he says, with only the faintest glint of irony. He does feel better about himself than he used to. Don’t we all? Surely we do.

Pitt reckons he is mid-way through his career. He hopes the choices will keep getting better as he gets older. “The directions get clearer because new guys come along and there is not that frenzy or that heat anymore,” he says. “It’s like the haze clears and you can focus. And I guess I focus on the work, not the game.”

His initial upswing, he says, happened with Thelma and Louise (1991), in which he came in as third choice—well after William Baldwin, incredibly enough, who left to play the lead in Backdraft—to be the hunky drifter who gives Geena Davis a taste of sex and robbery. “Getting into it, I knew it was quality,” he says. “It was being let in the door.”

His filmography since, however, has been a motley collection. Just before he made Thelma and Louise, he starred in Johnny Suede as the eponymous hero, an amiable but dopey style stud with a fondness for suede, alongside the then unknown Catherine Keener.

“Then I did just a garbage film called Cool World which was a half-animation thing. Then I went into a River Runs Through It (1992), which was another nice break.”

It was, but as he worked across the genres—from Contact to True Romance, from Twelve Monkeys to Sleepers—he rarely cracked films of the edginess those first performances suggested. Even in recent years, for every Fight Club (1999) there has been a Snatch (2000). As for Troy, he thought he had a better leap in while he could still do a bit of incredible swordplay, not to mention cutting it as a demi-god. “I do start thinking that way. And say, ‘Fair enough, so let’s go all the way out on it and have some fun’.” Fun means learning to fence; fun also, more surprisingly, means reading the Iliad.

It seems terrible to say this should be surprising in anyone, but Pitt seems such a midnight cowboy, such an aw-shucks kid come to the big smoke, that you may forget—if you ever knew—that he was a journalism major at college. It is great, he says, to have such top-notch material for working on the character’s backstory.

And in those times between shoots, his big enthusiasm is architecture. It has been his recreational study for more than a decade. “I’m a bit nutty with it,” he says. “It’s a little preliminary to really get into it, but I have what you might call a little Bauhaus group of guys and we’re taking on some projects.”

It isn’t that he wants to stop acting at any point, more that he doesn’t want to take up golf, “the sport of the religious right”, as he once put it. You have to set limits on the Hollywood craziness somehow.

All this is, however, by the way. Pitt is really here to publicise Dreamworks’ latest animation, Sinbad, Legend of the Seven Seas, in which he gives voice to the flawed hero. That is one hell of an expensive voice, given that Pitt’s quoted salary as Achilles is $26 million. It is also rather a risky one because Pitt says himself that he has never had that kind of training. “Certainly, voice is not my strong point,” he says, comparing himself unfavorably to Joseph Fiennes, who voices Sinbad’s long-lost childhood friend. “people who have worked in theatre, where there is a lot of emphasis on the voice, have worked out the kinks. I haven’t had that, so I was surprised when I was asked but I thought what the hell, I’ll give it a shot.”

Why? Because he could see that animation was hot; that was where the technical innovation was happening and that good actors were getting into it as a result. Because he has nieces and nephews he would love to be able to show something by Uncle Brad. That’s why. Anyways, as he says, there is room for everything. His next film will be Doug Liman’s Mr and Mrs Smith, where he co-stars with Nicole Kidman, back in the action genre.

Once he started Sinbad, he says, he realized how easy this voiceover lark was. Really, he says frankly, doing Sinbad was more like reading aloud than acting. “It’s right there in front of you. We take several cracks at it, they throw in ideas and you really just make it up as you go along.” It’s the animators—400 of them on this film—who do the real work. “I’m sure a more respectable actor would put a lot into it,” he says, shuffling boyishly in his chair as if he can’t keep schtum any longer, “But seriously! Me, I thought we were all just having a laugh, really.”

All modesty, says Dreamworks supreme Jeffrey Katzenberg. “He doesn’t understand how gifted and talented he is and how big a contribution he was capable of making. Brad Pitt was the dream persona and personality and acting quality for that part. There wasn’t a second choice.” But does an animated Sinbad need a megastar behind him? “I ask you to step back and think for a moment,” says Katzenberg. “The reason why stars have become such big names is because they’re the best.”

Goodness me, there is a lot of nonsense talked in Hollywood. And there is a special sort of nonsense reserved for the likes of Pitt, mostly to do with being a demi-god in life as well as in art. He has been named one of the top 100 movie stars ever (Empire Magazine), the 50 most beautiful people in the world (People magazine, two years running), the sexiest man alive (People, again, twice—you gotta love those guys) and one of the 100 sexiest movie stars ever (Empire). Yet somehow, he doesn’t actually seem half as nuts as you would expect.

OK, there was the million-dollar wedding to Aniston and the subsequent dispute with the jewellery firm that made the rings to Pitt’s design (and then started flogging replica Brad ‘n’ Jen rings to the punters), stories that are very much the stuff of a Planet star. On the other side of things, though, he describes himself as a homebody. He and Aniston are planning to go to cooking classes together “because we’re both crap in the kitchen” and he does, he admits, have a bad habit of resorting to snacking on cereals.

And it isn’t so remarkable that he is so settled, he says, because he was never the rambler people assumed. “I’ve never been that guy. I have a great base, with great friends and a great wife.” Before he met Aniston he had a few long-term, high-profile relationships with colleagues. He and Juliette Lewis, his co-star in the TV movie Too Young to Die? And Kalifornia (1993), were an item for a few years; in 1996, he was engaged to Gwyneth Paltrow, whom he met during Se7en. After they split the following year, any question about him could reduce her immediately to tears, but she never said a word against him. If he played the cad, nobody is saying so.

Troy is the first film Pitt has made, apart from recording the voice for Sinbad, in two years. He is finding the business of uprooting to a location tough. “I like my home. I used to love to travel and explore; I’m in Malta now and there are 5000 years of history there and it’s fantastic, but it gets harder as you get older. And I’m sure with kids, I’ll come home more.” He and Aniston have said how keen they are to have children, so presumably they have their shoulders to the wheel.

There are rumours, of course, that Pitt has spent good money on prolonging those youthful looks. He doesn’t quite deny it. Given they are his living, it would be strange if he hadn’t.

“There are people in this business who run from age,” he says, absentmindedly stroking his smooth cheek, “and you see the detritus left over from that. The denial, I guess. I don’t know yet, but there is that time when you gotta let go, man. Mick, come on! You know?”

In the meantime, thought, there is a Pitt fighting the Trojans in a tunic. He isn’t letting go yet. “Those Greeks, they liked the mini,” he says, grinning that sheepish Thelma and Louise grin. “Not only that, but apparently they fought with all the tackle hanging out. They didn’t mind it a bit.” So did the costume department make his underwear decisions? “This is not Caligula. So they got it strapped down.” What he just couldn’t understand, he goes on with mock thoughtfulness, was how it was that the Trojans got to wear much longer tunics than he did. He fought his case—“when we’re debating the old hem lines, I’m throwing everything in, man—but those designers pulled rank. How and why that should be is the business of magazines, such as People and Empire, that keep track of sexiness and starriness and number their stars out of 100. For the rest of us, let’s content ourselves with saying that even if Pitt isn’t going to be on a horse this time, there is clearly going to be some compensation on offer. The Greeks come, as usual, bearing gifts.