Alan Cumming: The flying Scotsman

When he's not firing off his latest novel, or presenting his own chat show, he has Hollywood and Broadway fighting for his acting services. Not bad for a nice boy from Carnoustie who started out in photo love stories for Jackie...

The poster for the film X-Men 2 features a dozen strutting and posing superheroes – called things like Storm and Pyro and Rogue and Wolverine – in improbable haircuts and sub-Starlight Express costumes. They are all frightfully earnest, determinedly cool, desperate to impress as they advance on the camera. Right at the back, so small that he's hardly there at all, is a lesser being, a blue-faced goblin, peeping nervously round the figures in front of him. The least important of these self-important Olympians, you'd think – yet at key moments of X-Men 2, Alan Cumming's character Nightcrawler manages to upstage his more glammy and gung-ho compadres. In a platoon of attitude-striking übermenschen, he is the only recognisably human figure.

Not that he looks very human. His entire body is covered in blue pigment, his skin is embroidered with a swirly frieze of tattoos, his ears are pointed like Bowie knives, his eyes glow with a mad white gleam, and his mouth, crammed with sharpened white fangs, upstages all around him. But he's a character with depth: a mutant German ex-circus performer, once called Kurt Wagner, with a vestigial religious belief who quotes the Psalms at moments of stress ("Zo I valk sroo zer valley of zer shadow of Dess, I vill fear no eefil", in his amusingly Cherman delivery). He is by turns fearful, emotional, giggly and subversive.

Quite the oddest thing about him, though, is to find Alan Cumming behind the blue slap. For Mr Cumming is nobody's dream of an action hero. The Sardonic Friend, yes. The Untrustworthy Boyfriend, sure. The Smirking Movie Director, by all means – but not the Mad Mutant with scary powers who tries to assassinate the President in the opening scene.

"I know, I know," says Cumming, lighting an American Spirit ciggie in his suite in the Dorchester in London. "I was doing a junket in America, and I met this guy who said, 'Alan, I've seen you in a lot of roles, but this is the first time I've seen you open up a can of whup-ass.' I said, 'Sorry? Do you spell that with a U or two Os?'"

Cumming bridles. Whup-ass, indeed. Nightcrawler is no muscle-bound hero. He saves lives, by teleporting himself from a speeding jet or by disappearing through the wall. Did he, as a scrupulous actor, feel that he "understood" the character? "I didn't when I first read the script. I had no idea, because I hadn't read the comics or seen the first film. I didn't even know that Rebecca's character [Rebecca Romijn-Stamos as Mystique] is actually his mum. Nobody told me that until two months into the film. But I know Kurt was abandoned, and taken in by a circus to be a freak-show, and I think he turned to religion as his way of dealing with being treated badly by people. And I foolishly insisted that he should have the tattoos done – done by himself, to atone for his sins – but it did mean two extra hours getting the fucking things done."

Oops. We have strayed into dangerous territory. The memory of his make-up sessions drives the normally charming and equable Cumming into frothy rage. "The face was done, oh, 40 times, four hours of make-up each time, and I had to get up at 2am to be ready the same time as everybody else..." Was it all worth it? "A lot of the time, it's just boring because those big action sequences take for ever to do, and it was a long, long shoot, so you kind of lose sight of reality. I spent weeks just wandering around corridors or flying through the air or killing someone. So it's not very fulfilling intellectually or emotionally." He reconsiders. "Well, it's emotionally draining because you want to cry all the time, about having to get up at two in the morning. But when I saw the opening sequence, I was laughing my tits off. Because, you know, you don't expect to be a superhero. It's not really the, ah, logical career path you might have expected."

He is refreshingly unserious about the logic of characters with special "powers". At one point he has to carry the wheelchair-borne Professor Xavier (Patrick Stewart) to save him from danger – "and, yes I know, it's hilarious, isn't it, because we're all, like, superheroes, right? So why am I carrying him when I could teleport him? And Halle [Berry, playing Storm] has to run up these stairs before the dam explodes, and she's wearing heels and the stairs are, like, metal grid, so her heels were going through them. It's all a bit... un-superhero-like."

He chuckles. Cumming is delightful; playful, forthcoming and indefinably seductive. He seems a chap constantly on the lookout for a good time. And he has a (much deployed and probably much-practised) killer grin, like that of a lecherous pixie. He has a reputation for either tactlessness or for speaking his mind, depending on your point of view, which, today, leads him to dismiss the whole fantasy-blockbuster genre: "I probably wouldn't go and see this film if I wasn't in it. It's not really my bag." Would the producers of X-Men 2 mind him saying that? "I don't know. I don't really care. People ask me questions about Spider-Man and Daredevil and I've not seen those either. But then quite a lot of the films I've made I wouldn't go and see if I wasn't in them."

There are lots of Cumming movies around, even if many of his appearances are cameos and walk-on parts. He was the oily boyfriend pitching woo at a plump Minnie Driver in Circle of Friends; the queeny desk clerk in Kubrick's Eyes Wide Shut; the Russian baddie in Goldeneye; the Reverend Elton in the Gwyneth Paltrow Emma; and – a bit of a career barrel-scrape, this – a green alien called The Great Gazoo in The Flintstones in Viva Rock Vegas. "I'm a sort of oddity in Hollywood," he says, "because I'm different in each film I make. When I first started doing promotions, people seemed to think that was weird. For me, it's just what being an actor is."

He was classically trained at Scottish Rada, after a brief flirtation with journalism. He had a lonesome childhood in the Highlands around Carnoustie, growing up miles from any company, with an angry and demanding father and a brother who was too much older to be an ally. At 16, he joined a pop magazine called Tops, for which he interviewed bands, and he turned up in the photo love stories in Jackie. "I usually played nice boys – I was often the boy at the side of the dance floor looking forlornly at the girl. When I was 17 I looked about 12, and it was pretty obscene actually."

Switching to drama, he found his métier – and his wife, a fellow student called Hilary Lyon. With his friend Forbes Masson, he formed a double act called Victor and Barry that went down a storm in Edinburgh in 1987. With Hilary he moved to London, settled into Crouch End domesticity and found himself playing Hamlet to her Ophelia at the Donmar Warehouse. Fame and applause and awards followed – but so did a succession of panic attacks and depressive interludes that culminated in a nervous breakdown. He left his wife, moved to a flat in Islington and started to rebuild his life, and resume his energetically bisexual lifestyle. And then came the call to do a movie called Circle of Friends, on the set of which he met the lanky dreamboat Saffron Burrows, whom he courted for two years...

Cumming has distilled some of his mouvementé life into his novel Tommy's Tale, which was published earlier this month. It's the (clearly autobiographical) account of a north-London bisexual who lives with two madcap chums in Islington, does parties, drugs and sex, and suffers awkward promptings of seriousness and hankerings to be a father. It begins with a significant little fairy tale about a man who realises one day that he missed out on being a little boy and decides to embrace his little-boy side. Had childhood been the same for Cumming? "I had to be an adult in the sense of having to understand adult things, to be aware of adult things and get a grasp of stuff going on around me, about my parents. I didn't feel that I really was able to play enough when I was young."

You realise, Alan, I said, you sound a tiny bit like Michael Jackson? "Yeah, but I think I'm more balanced than that. I think I'm lucky in having embraced this thing about playing, having fun, needing that balance in your life. I think it's very important, the need to let go and have a good time – how it fuels the rest of your life. Especially as an artist – you can understand a lot of stuff about yourself in that letting-go, and you can use it later on."

Apart from the odd burst of thesp-speak, Cumming is very direct about his life, even about the problematic area of his sexual orientation. Every interviewer wants to know if he's gay or straight or both. But he can't avoid the subject, because "I get really pissed off with people who are gay but won't talk about it. By denying it, you're saying there's something wrong with it. It's so harmful propagating the message that there's something bad about it."

He is stridently unashamed of anything he has ever done in the sack or thereabouts. "I think there's so much shame attached to sex and sexuality, and that's terrible. As I've got older, I've been more aware of how it affected me when I was younger and I've grown out of it, thought about it and realised that there should be no shame attached to it. So I try to provoke people to reassess their views about these things."

He started out "skirmishing" with boys at 14 or 15, but enjoying his first horizontal jog with a girl at 16. "Both the skirmishing and the shagging were really lovely and shame-free experiences. I enjoyed them both equally. Well, I enjoyed the second more, the girl, because it went on longer, and she was older and experienced and, you know, good at it. I was very lucky. And from an early age I saw how your desires are inexorable – that if you suppress them, it just causes you and others pain."

So Cumming has been letting it all hang out. He has, in consequence, become a celebrity in New York, where he's lived since knocking 'em dead as the grotesque, camp MC in Cabaret in 1998 – a transfer from the Donmar Warehouse. He cannot walk down Fifth Avenue without being mobbed. His ubiquity on late-night talk shows led to him hosting his own – Eavesdropping with Alan Cumming – where, because of his wide social acquaintance in Hollywood, he can invite, say, Halle Berry to come on and chat about her breasts. "We were having a debate about plastic surgery, and I said, 'Okay, Halle, let's talk about your boobs now,' and she's like, 'Okay' and I go, "They're so great, they almost look not real...'"

He's so much a part of the Manhattan landscape that he was given a cameo in Sex and the City as the snooty overseer of a Dolce & Gabbana catwalk show. And in an exercise that sounds, on paper, like an enormous celluloid name-drop, he co-wrote and co-directed The Anniversary Party with Jennifer Jason Leigh, starring their best pals Gwyneth Paltrow, Kevin Kline, John C Reilly and Parker Posey. He has projects queuing up, including a comedy movie with Catherine Zeta Jones about a flamboyant West End theatre queen who inherits a Welsh rugby team, and a TV comedy for Steve Martin called Mr and Mrs Nash about a couple of gay detectives. And he's now writing the screenplay to Tommy's Tale, the film rights to which have been sold.

Who will play Tommy? At 39, Alan Cumming, regrettably, is too old. But for a man so determinedly in flight from an unhappy past, and so devoted to the concept of fun, age is an irrelevance. Like Tommy, his fictional alter ego, he may be assailed by impulses to grow up and get serious, but he can, thankfully, consign seriousness to movie roles. "Of course I could play Macbeth. I mean, who you are as a person infuses your work, but as an actor it doesn't really matter. Because you immerse yourself in whatever you have to do, whatever is called for in the role. Last year I played the Pope..." And Mr Cumming grinned his irrepressible (and decidedly non-papal) killer grin for an invisible camera.

'X-Men 2' opens on 1 May