EWAN McGregor may be known for taking his pants off in the movies, but after meeting him it's me who is thoroughly debriefed. What colour, exactly, are his eyes? Is he more, or less, handsome in real life? Would he like me to have his babies? For the benefit of the female friends who asked, the answers are: a kind of greyish blue; more; aye, right.

McGregor, at 30, is firmly established as Britain's hottest film star. He mainlined to fame with Trainspotting, went off the radar somewhat despite making 13 films in four years, returned to prominence with the disappointing Star Wars: The Phantom Menace, and is now firmly back in public and critical favour thanks to Moulin Rouge, for which he has earned a Golden Globe nomination.

Six weeks before this interview, he became a father for the second time. On October 22, his wife Eve Mavrakis gave birth to another daughter, Esther Rose. He tries to have his family around him even when he is working, and while we talk over coffee in London's Claridge's hotel, the baby can occasionally be heard crying in an adjoining room.

'When Clara was born (in 1996) I was working three weeks later in LA,' he says, running a hand through his spiky hair. 'And that's the last thing you ever want to do. Especially when it's all brand new, and you don't want to leave her and your wife. That was really tough. But when you are making a film that is all of your life. It's very difficult to have time for anyone else.

'You see them asleep. I was cursed with that for the first three years of Clara's life. Because I was working all the time. I'd see her sleeping when I left and see her sleeping when I got home. So I've been lucky this time. I haven't worked since Moulin Rouge, and that was June. I've had half the year off, all through the pregnancy and the birth.'

It's true that McGregor seems more relaxed than he has for some time. He famously finished Little Voice at nine o'clock one evening, and started work on Rogue Trader at six the following morning. He made himself angry doing that, but those days are behind him now. His priorities have changed and, I'd say, he has lost much of the insecurity that he used to talk about in interviews in between making smutty jokes. Perhaps he doesn't feel the need to make so many films because he no longer believes his success could crumble at any moment.

In any case, moderation looks good on him. He's slim, almost Renton skinny, and dressed way down in blue jeans and biker boots. His eyes twinkle like special effects. He's a right laugh.

McGregor is here today to promote Black Hawk Down, his new movie, directed by Ridley Scott. The last time he spoke to the press was for Moulin Rouge, Baz Luhrmann's corsets 'n' consumption pop odyssey through fin de si�cle Paris. All anyone wanted to know was whether he had an affair with Nicole Kidman. In connection with that, I ask about an article in Esquire which quoted Luhrmann as saying Kidman and McGregor came 'very close' to becoming lovers.

According to McGregor this is a misquote, and furthermore, 'bollocks'. He's understandably aggrieved that he has to reassure the media that he wasn't unfaithful to his wife. Does it upset him that just because he's good-looking and famous, people assume he is sleeping around? 'Well, I choose not to let it upset me, no. If I did I would be f**ked. And my wife also is very stoic about the whole thing. Because otherwise it could completely ruin a marriage.'

The other day he and Kidman had lunch together in Los Angeles, only to find the restaurant besieged by photographers. McGregor affects nonchalance, but is clearly at the end of his tether about this stuff. 'People asked me this in the press line at the premiere of Moulin Rouge in Leicester Square,' he sighs. 'Nicole was on my left, and my wife was there with me. And I was speaking to this female reporter who said 'So look, c'mon, all the rumours about you and Nicole on the film?'. I said 'I can't answer your question. Look, she's standing right there and my wife is right here'. And she went 'Yeah, but she's so beautiful, come on'. Like, how could I possibly resist? She just didn't get it. I didn't punch her, but I can't say I haven't had a f**king fantasy about doing it.'

McGregor's attitude to celebrity is all mixed up. As a kid in Crieff he idolised James Stewart and Elvis (you can see a bit of both in the way he juggles boy-next-doorness with the sex god thing), and has always romanticised Hollywood's golden age. 'I love the idea of being attached to a studio and driving around in big cars with some really great parties to go to,' he has said. 'You really were a movie star then.' But in the next breath he will sneer, 'I can't stand LA and Hollywood and all that A-list nonsense. It's just about being famous, a product that's fashionable, not who you really are.' And then again, he'd really, really like to win an Oscar for Moulin Rouge.

THE schizophrenic attitude extends to his choice of films. There isn't any such thing as a typical Ewan McGregor movie. Junkies, Jedis, hapless hostage-takers, absinthe-addled poets with a thing for Bernie Taupin lyrics -- you rack 'em, he'll crack 'em. He loves making movies, and doesn't seem to have anything resembling a career plan, choosing projects purely for the pleasure he will get from making them. He signed up for Black Hawk Down because he had never made a war movie, and it was a way of gratifying the wee boy within, the one who used to play soldiers after school.

Then things changed. Black Hawk Down is an attempt at recreating the events of October 3, 1993, when 140 US soldiers were involved in a disastrous military operation in the Somalian capital Mogadishu. Abseiling from helicopters into a busy market neighbourhood, their mission was to abduct two lieutenants of the warlord Mohamed Farrah Aidid. By the next day, 18 Americans were dead and 70 badly injured. Over 500 Somalis were killed and double that figure hurt. It was a mess, enormous human tragedy which had a huge impact on US foreign policy. 'We were in no doubt that we had a very serious task to represent those that had fought and died there,' says McGregor. 'It became much more serious than playing soldiers.'

He and the rest of the cast, which includes his old Trainspotting amigo Ewen Bremner, prepared for the film by training with elite US Rangers. McGregor quickly developed a great deal of respect for the troops. At one point, the actors had to train for battle in a mock town, constructed at Fort Benning in Georgia. 'Using these skills that we had supposedly learned, we had to move from one end of the street to the next, with real Rangers popping up at the windows and firing blanks at us.' He laughs. 'It was chaos. We would all have been dead within seconds.'

Black Hawk Down was filmed in the Moroccan city of Rabat early in 2001. Since then, of course, this movie about America being involved in foreign conflict has taken on a more profound meaning. It's impossible to watch without thinking of Afghanistan, especially as al-Qaeda are rumoured to have had a hand in Mogadishu, and the US defence secretary has intimated that Somalia may be next on the list of nations targeted for harbouring terrorists. McGregor, who is opposed to any further invasions, is keen to play down the resonances of Black Hawk Down post September 11, but does acknowledge that it is now more important than it was when he made it. He hopes that the film, which is visceral in the extreme, will temper some of the gung ho excesses of public opinion about the war on terrorism.

Following Black Hawk Down, our next chance to see McGregor on the big screen will be in Attack Of The Clones, the latest instalment of the Star Wars saga. It's funny talking to him about Star Wars because he clearly has serious reservations about the films but can't quite bring himself to say so. Asking outright whether he liked The Phantom Menace is to witness one of our most loquacious actors being, for once, lost for words. After a Death Star sized pause he finally says 'Yeah, fine.'

He might as well be honest, I say.

'No, it was fine, it was alright. It wasn't quite as I'd ... I suppose I was ... No, it was fine.' He chuckles like a choirboy who's farted in church. 'I have to be so careful because they come down on me like a ton of bricks.'

Does he feel under pressure to get it right with Attack Of The Clones? 'I don't feel under any pressure. That's all George Lucas's pressure.'

But surely, as one of the public faces of the film, it will be McGregor who has to take responsibility if it's no good? 'I suppose, but I still don't feel any pressure. I really don't. I think there was much more room for us to play in Episode II, and that's certainly something that needed to happen. There was something very humourless about The Phantom Menace. Everything was so straight and flat. And certainly in Episode II there is much more room for expression and wit. We had more fun. There's more humour in there. It's warmer and has more of a traditional Star Wars feel to it. More battles and ... you know, I shouldn't give anything away really.'

We talk about directors -- George Lucas and Ridley Scott, Baz Luhrmann and Danny Boyle. He and Boyle have not worked together, or apparently spoken, since Leonardo DiCaprio was cast in The Beach, a part that was originally intended for McGregor. It was the end of the team, along with producer Andrew Macdonald and writer John Hodge, that had crafted Shallow Grave, Trainspotting and A Life Less Ordinary.

Does McGregor miss Boyle? 'Um, yeah, I do. I miss working with Danny.'

I say that I thought they had a really good creative partnership going for a while. 'Mmm,' he deadpans. 'So did I.'

Is there any chance that the Trainspotting team will ever work together again? 'I've no idea. I don't know, really. Who knows?'

Both sides have always maintained a diplomatic silence about the Beach breach, but today McGregor seems to want to talk. 'It was badly handled, all that stuff. All of that was a disaster really, on their part. Disastrous. The way that they dealt with me was awful. They didn't deal with me at all.

'I was gutted. It was just when I looked back and realised all the lies and deceit that had gone on, I thought 'Aw, f**k you'. I didn't care about the film one way or another. But the way they dealt with things in terms of me, firstly being part of their team, and secondly being friends with them all, was shocking. I mean I was actually quite shocked by it, and that takes a lot of repairing.'

It's arguable that this rift caused McGregor to lose his way as an actor for a while. No way, he says, but it gave his confidence a knock, and affected him personally. 'I could have become really cynical and never trusted anyone again, but I decided I wasn't going to do that, and let them have that power over me. But for a while I was thinking 'God, if you can't trust your friends, who can you trust?' Which, funnily enough, was what the first two films we made together were about. Isn't that funny? The betrayal of friendship was at the core of Shallow Grave and Trainspotting.'

McGregor has been famous for six years, and it has been a steep learning curve. 'A lot happened to me very quickly,' he says. 'I became successful, I became a husband, a father, a house-owner, all at the same time. Bosh!' He found it confusing, difficult to get used to, not at all like sliding your slippers on.

'Life was, for me, quite frenetic for a long time. I made a lot of films and I ran around a lot and f**king drank too much and did all that stuff. I didn't go off the rails, but I spent a lot of time with people I didn't like, going out to places after work and ... I did too much of that. When, in actual fact, I've now realised that all I ever wanted was at home. It's not a big deal about turning 30, it might happen when you're 40, I'm just lucky that it happened to me now. I feel more settled and happy with my lot. Christ, I've got a lot to be happy for.'

It's weird to hear him talk like this. McGregor has never given the impression that he had any difficulty coping with life in the spotlight, or that his boozing was anything more than harmless letting off of steam. Well, there was that time at Sydney Mardi Gras where he jumped around in a leather catsuit, with a faceful of slap and a fistful of lager, but apart from that he's always seemed such a level-headed chap.

Even back in 1993, during his first ever interview with The Herald, he seemed very keen to bodyswerve the perils that could turn a young him into a narcissistic swine: 'Some people in the business want you to be the archetypal new, young actor, encouraging you to take loads of drugs and screwing everything that moves.'

He nods when I mention this. 'I was always aware of that,' he says. 'I can remember feeling that that was wanted of you. Me and my mates used to go out with a bunch of casting directors on Friday nights. And I remember for a long time they all thought that I was having an affair with Jude Law, and it was almost that they wanted that to be the case. Occasionally we'd play up to it because it was so funny. I said to him 'I think everyone thinks we're having an affair', so we'd give wee looks to each other at dinner and stuff.'

Well, Jude's a handsome man.

'He's a lovely man, yeah. And my cup of tea I'm sure if I were that way inclined.'

MCGREGOR'S extended tea break will come to an end in March when shooting begins on Young Adam, an adaptation of the novel by Scottish beat writer Alexander Trocchi. Co-starring with Tilda Swinton, McGregor is to play an enigmatic young loner, working on a canal barge, who drifts into murder and blank sex.

He says that Young Adam is a very erotic book, but I thought the sex was written dispassionately and carried out mechanically, entirely devoid of emotion. 'Yes, exactly,' he laughs. 'Which for some reason I find very erotic. And the sexual encounters really mark his decline. They just get colder and colder and colder until it's just an act like any other. Like in Moulin Rouge the singing tells the story, the sex does in this. They are not just sex scenes in a movie. They are actually very powerful devices in showing this guy's collapse.'

We talk a bit about his sex scenes in other films He reckons that most have had some point to them, except perhaps for his debut. 'The first one I ever did was in Lipstick On Your Collar. That was funny -- just a quick ride on the table with Louise Germaine.' He chortles. 'A quick shag, which is exactly what it was ... I mean meant to be!'

Although Young Adam should have been completed by now, production was put on ice when funding fell through. It's partly set in Glasgow, and was to be filmed there, which would have made it the first of his movies shot in Scotland since Trainspotting, but it may now be made in Ireland. 'We lost this money from a private investor guy who'd signed up,' says McGregor. 'I wish I knew his name so I could slander him all over the place.'

Sigma Films were short of $1.8 million, and had a hell of a time finding the cash. According to McGregor, the British Film Commission said that they would make Young Adam for a million dollars with no stars. In other words, ditch the famous Scottish guy and you've got yourself a movie. 'I was rather upset by that because I felt that I really have stuck by British films, and half my success is marked by those I've made. So I felt really let down.'

He's still clearly annoyed by the difficulties that have beset production. 'This film is such a huge opportunity for us in Britain. But it seems that at the moment there's a mandate come from somewhere saying that we're only supposed to do quirky, American-style romantic comedies.

'But now I just think, f**k it, who cares? What is the British film industry anyway if it's in such a state that we can't be doing diverse, interesting stuff? To me, in my working career, British films have always been slightly off-the-wall, powerful movies. And now if it's the case that we're only meant to do romantic comedies with stammering, stuttering leading guys, I don't really care any more, and I'll do films wherever.'

British cinema without its favourite son? Nobody around but Hugh Grant and Colin Firth to keep our upper lips stiff and our cockles warm? It's a sobering thought, and one to dwell on if we had the time. But we don't -- Esther Rose is crying, Hollywood is calling, Jude Law is batting his eyelashes, and Ewan McGregor, with the briefest of handshakes, is disappearing out the dooru

Black Hawk Down is released on January 18. The Golden Globe Awards are announced on January 20