He'll never play the chisel-jawed leading man but Alan Cumming has a misfit's charm, a sideline in writing, an Olivier... and the gall to accept a big part in the new Spice Girls film.
Alan Cumming's entry in Spotlight, the actor's almanac, says he is 5ft 10in, has dark hair and blue eyes. This summer, he filmed a two- minute scene in the Stanley Kubrick movie Eyes Wide Shut, in which he plays a hotel clerk who forms an instant crush on Tom Cruise. As he gazed for three days on Cruise's iconically cheesy face, Cumming may as well have been lusting after a blurred mirror image of himself. Same-colour hair and eyes, same-size grin and (contrary to rumours circulating about Cruise's need for stack heels) roughly the same height. These are classic leading-man specifications, and yet the only leading man Cumming has ever played is in Hamlet, a play about a man who doesn't want the lead role.

Instead, Cumming is perpetually the geek, the creep, the nerd, the pout, the fop. Anything but the straight-up-and-down hunk. Last year, after making successful Hollywood-financed films over here such as Circle of Friends and Emma, he got the call to make two movies in LA. Producers over there had his number in no time. In Romy and Michele's High School Reunion, which opened here this week, he plays a nerdish millionaire with a crush on Lisa Kudrow, whose only moment of machismo comes in a wish- fulfilling dream sequence. Having got him to voice the horse in Black Beauty, the writer-director Caroline Thompson then asked him back to play a trainer of chimpanzees in Buddy. The script was adapted by Thompson from a book by Gertrude Lintz about bringing up a gorilla among chimps, and the film also stars Renee Russo and Robbie Coltrane. Training chimps sounds close to perfect casting: there is something about Cumming's impishness that is next to chimpishness.

"I'm always going to play weird people," he says. "But that's fine. When I read scripts I always find the part of the lead man dull dull." Thus in For My Baby, an arthouse film shot in Hungary last winter, he plays a stand-up comedian and son of Holocaust survivors who is in denial about his Jewishness. This winter, he goes to Broadway with the director Sam Mendes to reprise his saturnine MC in Cabaret, a three-year-old Christmas hit in the Donmar Warehouse. (Natasha Richardson will play Sally Bowles.) Lately, a script even landed on his desk fingering him for the part of Hitler.

Clearly, casting directors have taken his Bond villain - he played the dastardly Russian computer whiz in Goldeneye - as something of a handrail. "I can't tell you the number of films I got offered after that to play computer geeks." But just about the only people who have spotted any consistency in his role selection are the manufacturers of the headpieces worn by telephone operatives. He wore one in Goldeneye, and another in the BBC's Burn Your Phone. His picture has found its way into their trade magazine. "They think I'm just fantastic, because every film I'm in I wear their product."

Last, and possibly least in his gallery of misfits (though let's reserve judgement), he has slapped on a chest wig to play a posh maker of documentaries in Spice: The Movie.

Other actors might have shrunk from this particular offer, but not Cumming: "I knew that my agent might be a bit sniffy about it so I just told them, `If I'm offered it, I'm definitely going to do it; don't even try to dissuade me.'" (Brief tangent: when Cumming learnt that Ginger Spice had seen his Hamlet, he all but got a T-shirt printed to announce the fact.)

It would be easy to deduce from Spice and other sugary ventures that Cumming has simply gone for the commercial jugular. "Sometimes I do things for the money," he admits, "but I know why I'm doing them. I don't think something is Citizen Kane when it's not." But it's not always easy to square his frank pursuit of the dollar with the scepticism that formed a large part of the baggage he took to Hollywood. He talks with the bafflement of someone brought up in the remote Scottish countryside about the ritualistic comportment of film folk: the my-Winnebago's-bigger-than-yours syndrome, the power trips of certain co-stars, the inventory of on-set perks on his contract. "Rental car, mobile phone, trailer with a fridge, CD, microwave oven. It's like someone's doing their wedding list or something."

In the too-frank-to-publish journal he kept of his nine months in Hollywood, those things he found "bizarre and hilarious" in the first couple of months "weren't even mentioned as I went on because I was so used to them. The longer I stayed there, the more depressing I found it, because I can see how you get sucked in. You yearn for a conversation about something other than box-office grosses." After Romy and Michele opened, "I got all these phone calls saying, `Hey, congratulations, your movie took seven and a half million on the first weekend.' Or was it nine and a half? Who. Gives. A. Fuck?" The darker and more complex Buddy, meanwhile, has fared "very badly. There's no justice in that respect. If you spend too long in that world, you start thinking that films that make lots of money are good."

In the beginning, Alan Cumming made his name in stand-up. He formed Victor & Barry with the shorter, carrotier Forbes Masson, and in their Edinburgh Festival debut they were trashed in The Scotsman by none other than this newspaper's editor, Andrew Marr. They sewed a retort into the act to the tune of "Lucky Stars": "We can thank you, Andrew Marr, that you're not as smart as you like to think you are."

The Cumming-Masson liaison eventually came up with The High Life, the sitcom about in-flight cabin attendants that they wrote themselves. Its audience was ambivalent about its merits, but then so were its stars. "Some people really love it - it's scary how much - or they hate it. I think that's good. We wanted to call it A Load of Camp Old Pish. We really wanted to do something that was really tacky, and the people who were making it with us just didn't get it. The head-banging-against-the-wall part of trying to do something different and weird with the sitcom form is something that I would never want to repeat." The BBC have none the less pressed for a second series, while showing a red light to dramas by Sharman MacDonald and Ol Parker that Cumming was signed up to make. "My agent phoned up to see about them and they said, `Maybe, if he does another series of The High Life, it would be more likely that they'd go ahead.' Isn't that revolting?"

Alongside the cabaret, Cumming swiftly built up a name in formal theatre but, since his kid Hamlet and his camp MC, he has given the boards a wide berth. "When I came back from Hollywood, I really tried to do a play, but I haven't found anything I like enough to do here. When you've played Hamlet and the MC, there are very few roles that are going to be a challenge." It may be that he's not looking hard enough, but at least he can fall back on his auxiliary talent as a writer. When he takes what could be seen as a retrograde step into Cabaret, he will continue in New York to workshop a one-man show "about loneliness" that he spent last week developing at the National Theatre Studio.

Actually, it's not quite true to say he hasn't been on stage in years. He gets asked to hand out a lot of awards. "They are never there, the people I give them to. They say to you, `And so, Alan, will you take it and keep it for them until you see them?' And you think, fuck, I've never met them in my life before, and you go, `Yes, I'll hold on to it.' I was so tempted to steal a Bafta. I walked off the stage and no one takes it off you and I thought I could go to my dressing-room and just put this in my bag. Imagine having a Bafta on your mantelpiece and you'd stolen it."

He hasn't been on the receiving end of an award since his Olivier for Accidental Death of an Anarchist at the National. Buddy, though bringing a rare taste of box-office rejection, has none the less earned him trophies he can display at home. The film required him to get to know the quartet of chimps whose keeper he played in the film. "It was like I was a nanny for four kids for a few months. One of them was absolutely in love with me: Tonka, as in the trucks. When they really like you, they want to groom you, and they want to play with you. He would pick up my hand and hit my hand on his head so that then he could be justified in hitting me so we could start playing. I felt so flattered. I even took my chimp Polaroids in to show Stanley and Tom [Kubrick and Cruise, in case you're wondering]." Tonka is also an artist. His keeper faxed some of his work to Cumming's hotel in Budapest. "And I've got two paintings that he did in my bedroom." And is he talented? "He shows a lot of potential."

`Romy and Michele's High School Reunion' is on general release