Ewan McGregor: Bloomin' Nora, this man's a star

Hollywood loves him, but is Ewan McGregor - the subject of a FilmFour season - really that special? Mark Kermode thinks so

The first thing that happens when I meet Ewan McGregor is that I give him the horn. Literally. The horn in question is one of a pair of battered cors anglais which I have been dragging around since my days as the worst French horn player in school, desperate for the chance to say "Oh, you play the French horn too? Well it just so happens that I have a couple of horns with me. Care for a duet?". Since McGregor famously made his TV debut aged 16 as a spike-haired horn player, then graduated to playing a convincingly musical miner in Brassed Off, and even directed a short film about the communicative power of the trombone (Bone) I figure this is my chance and pounce. To his credit, McGregor fiddles gamely with my rusty instrument for a moment before politely pointing out that all three valves are stuck fast – the result of not having been played for more than a decade. So that puts paid to that.

The failure of the horn ruse is a blow because it fostered my fantasy that I have loads in common with McGregor, when in fact we are worlds apart. Physically, we might as well come from different planets, he being the possessor of a spectacularly watchable body which he has gloriously flaunted in a wide range of public places: from a stage in Salisbury in What the Butler Saw ("Fantastic, especially the matinees – there is nothing like being naked on stage in Salisbury in the afternoon!"); to the cinematic canvas of Peter Greenaway's The Pillow Book ("my dad sent me a note saying 'The movie was beautiful and I'm glad to see you've inherited one of your father's main attributes'"); to the open-air rock festival sets of Todd Haynes's gloriously unruly Velvet Goldmine ("I hadn't really planned it, but I was on stage, and then my trousers fell down ...").

The unabashed ease with which McGregor inhabits his skin is symptomatic of a winning charm which has seen him land plum roles in such American blockbusters as the Star Wars prequels (The Phantom Menace, the forthcoming Attack of the Clones) and Black Hawk Down, while still retaining the down-to-earth credibility and reputation of a British actor of substance and integrity. Ask him which movies he enjoyed making most, and he'll wax lyrical about the comparatively overlooked Blue Juice, largely because it involved hanging out in Cornwall with pals Sean Pertwee and Steven Mackintosh, and catching amusing bacterial diseases from polluted sea water. "What a mad time," he laughs. "I loved it. I made a film with four of my mates, went surfing, and got a disease in the nose! Fucking brilliant!"

As for his proudest screen moment, he opts not for wielding a light sabre but holding the clapperboard on the first day of filming Nora, in which he starred as James Joyce, and which he also produced under the auspices of the Natural Nylon film company. "We set up Natural Nylon to make movies in the way we wanted to make them," he says of the company founded by Brit-packers Sean Pertwee, Jude Law, Sadie Frost, and Jonny Lee Miller. "We didn't want to have to pander to the States, which is something I think causes a lot of British movies to suffer. After all, they don't try to make films that appeal to us, so why should we worry about them?"

McGregor became the touchstone British actor of his generation in the mid-1990s playing the heroin-addicted Renton in Trainspotting, a film which had as much cultural impact as Kubrick's epochal A Clockwork Orange. The comparisons are particularly apposite since the one actor to whom McGregor bears comparison in both style and significance is Malcolm McDowell, the screen genius who achieved iconic status as A Clockwork Orange's anti-hero Alex. Like McDowell, McGregor is blessed with a faux naive smile in which the camera captures both childish innocence and adult corruption. Both actors too have what used to be called "perfect radio pitch" – mellifluous, sing-song voices which can lift and carry a drama, and make even the most alienating screen behaviour (violence, drug-taking, impromptu singing) seem sympathetic or acceptable. And while McDowell helped director Lindsay Anderson to change the face of British movie-making with If... and O Lucky Man!, so McGregor's formative association with director Danny Boyle seems equally crucial to the birth of the so-called New British Cinema.

"I loved the way Danny worked with actors," says McGregor with relish. "On Shallow Grave we rehearsed for weeks before the shoot, then again on set, with nothing fixed. And only then would Danny call in the crew to discuss how to shoot the scene. That still strikes me as the best, and most satisfying way to make a film. Even on a 'big' production like A Life Less Ordinary, I'd be on set and I'd see Danny, and I just felt good that he was there." It's notable that the only time McGregor seems lost for words is when The Beach is broached, another "Trainspotting Team" production reuniting writer John Hodge and producer Andrew MacDonald, for which Leonardo DiCaprio was inexplicably (mis)cast in the lead. "It was badly handled," confesses McGregor with palpable sadness. "It was a friendship issue, not really to do with the film. But as a result we've not seen each other since."

This is a real shame, and one hopes for a creative reunion soon. In the meantime, McGregor remains that rarest of things: a genuinely British screen star who knows how to play Hollywood, but is still willing to fight the good fight here at home. That's French horn players for you.

'The Ewan McGregor Interview', with Mark Kermode: FilmFour, Saturday at 9pm. A season of his films, including 'Shallow Grave', 'Trainspotting' and 'Nora', runs on FilmFour, 13 to 21 April