Firth Among Equals The brooding Mr Darcy has swapped his wet shirt for  wet nappies, domestic bliss  and comedy. But can Colin Firth  forget his first love: drama?

How has the actor acquired his sex-symbol pedigree when he neither smoulders nor sizzles, merely grins in an ordinarily pleasant sort of way? The camera, and the ministrations that precede it, somehow transform him, giving Firth younger flesh and an older soul, and he has learnt to perfect that suggestion of still waters running deep, the solemn mouth hinting at an ocean of manly forbearance.

The director Oliver Parker has used Firth's looks, and our reaction to them, in the upcoming The Importance of Being Earnest, where he plays the secret bon viveur Jack Worthing. 'You must believe that Gwendolen really falls for Jack, otherwise she's a twittering deb with a peculiar attachment,' says Parker.

Does it alarm or amuse Firth to be the commonest wet-shirt fantasy since Samantha Fox? He laughs: 'You can be quietly smug about it... but to be honest I've never been thought particularly good-looking.' Come, come now. Barnaby Thompson, the producer of both Earnest and Firth's new romantic comedy Hope Springs, insists that when People magazine listed him as one of the '50 Most Beautiful People' last year, Col' was cock-a-hoop. Today, tall and skinny in his perennial black jeans and jumper, he is in charming 'Welcome to my movie-star trailer' mode, the smile all the more winning for the lack of Beverly Hills dentistry.

Surgical enhancement of any kind is a no-no—'It gives me the creeps'—for an actor sauntering into his forties playing leads in nice-natured comedies and getting rich. He is also getting craggier, but when did that ever trouble a male actor's career? He'd love to play Heathcliff anyway.

Movie actors who laugh at your jokes are rare, and this one is as sweet to the wardrobe lady who brings in his costume as he is to the media. (Not like that Kevin Costner, says one of the technicians, dazzling with the press and stroppy with the crew, and as for Kevin Spacey... ) And why shouldn't Firth be beaming bonhomie at this charmed juncture in his 42nd year? There is chatter that the new films, both American co-productions, will tip him into Hollywood's leading-man bracket. After years of Hackney flats and empty fridges, he is established in a fine Islington town house. After a much-reported love life, he is newly, irrevocably domesticated.

His Italian wife, Livia Guiggioli, a documentary producer who is a decade younger 'but much more secure than me', gave birth in March 2001 to a baby son, Luca, a half-brother for William, his son by the actress Meg Tilly. 'I don't have an adviser,' smiles Firth, the family man. 'I talk to my wife.' She is moving into feature-film production, and his eye for adaptable books and scripts will be pillow talk from now on. He is happy, then? 'Yeah, I only ever wanted to be happy... Not even that, just a decent level of contentment. The baby has been fantastic, the best thing and the main thing, nothing complicated. My life revolves around my two boys. Everything else matters less.'

We meet in Battersea Park, London, on the set of the big-budget Warner Brothers comedy London Girl, [sic] a remake of Vincente Minnelli's The Reluctant Debutante. It's Firth's first work after a seven-month 'break' of sleepless nights and nappy-changing, but its star seems less than thrilled with the studio product, where rushes are beamed back to LA for corporate approval. It's fine, he says neutrally, Eileen Atkins and Jonathan Pryce are in it. But reading between the lines, he took it for the money and because staying close to home matters. These days he doesn't go out on a Saturday night, prefers Tuesdays when nobody's around. He is after an easy life, no unnecessary sorties outside his comfort zone, thank you.

'I'm trying to make choices for home and stability,' he says, knowing full well the benefits of such caution—and its price, feeling haunted by the spectre of the challenges he should be pursuing. Once terrified that bourgeois comforts would dull his creative edge, he now takes a pragmatic view. 'If I need to visit my elder son in California, I can afford it. I still don't have a fixed pattern of when I can see him: I have to make that time, choose not to work then.'

Not so long ago he was unthinkable comedy material, too dark, too moody, a face made for pin-ups, not laughs. Now lightweight scripts are flooding in, attached to lucrative offers, and it is suddenly hard to picture him as the brain- damaged Falklands veteran he played so powerfully in the 1989 drama Tumbledown. He won a Bafta for it and craves that intensity again. He admits to having envied Ralph Fiennes at times, would have killed for that role in The End of the Affair. 'What I'm doing now is paying the bills nicely, but I would like to get back to drama.' And will he? 'I know people are saying, 'Why is he doing comedies? He's making bad choices.' I'll have to go against the flow big-time if I want to change direction. It'd be turning round an ocean liner.'

Firth's favourite showbiz anecdote concerns George Bernard Shaw's visit to 1920s Hollywood to meet Sam Goldwyn. After three days, Shaw informed his host that they couldn't possibly work together. But why, inquired the shocked movie mogul. 'Because you're only interested in art and I'm only interested in money,' replied Shaw. For Firth, that inversion of expected characteristics says everything about Anglo-American movie détente, and he has definitely crossed the Atlantic that separates cash and culture.

Firth has worked consistently since leaving the Drama Centre in 1982 and walking straight into the play of the year, Julien Mitchell's Another Country, in which he replaced Rupert Everett as the public-school proto-traitor Guy Bennett. 'That fairy godmother never appears again. It dwarfs what Pride and Prejudice felt like. I went from nobody knowing who I was, and everyone doubting me, to my dad taking photos of the poster on Finsbury Avenue.'

His teacher, the theatre director Christopher Fettes, acclaimed his protege as a 'young Paul Scofield' and warned him off the moribund destiny of the matinee idol, which he could all too clearly see as a possibility. If only, sighs the golden boy in silence. His was the only Hamlet the Drama Centre ever staged, remembered by one in the audience as 'incredibly dark and glamorous', but plans to reinterpret the role with Fettes directing last year were shelved to make room for Hope Springs. Does he regret not fulfilling his dramatic potential? 'Oh, you know... Christopher was probably right.'

On being cast in Another Country, the young actor's ego fought with his embarrassment. All his drama-school contemporaries were either unemployed or doing less starry work, and they assumed he would change overnight. 'In the end, even I was waiting for my 'Hyde'. I bought the drinks for a long time. I had to be grotesquely humble, because if I'd forgotten to return a phone call it wasn't because I was being scatty, it was, 'It's started with Colin.' It was only a bloody play!' As for the film version, for which we imagined upper-class baby actors being hand-fed toast and honey by tender matrons, it was apparently more like a school field trip. For everyone, perhaps, except the sophisticated sybarite Rupert Everett, who was well ahead of the game in 'extracting maximum pampering' and intimidated the arty Firth into a taciturn withdrawal. Three years later came the offer he thought would change his life, Milos Forman's 1989 Valmont, where he met and fell in love with Meg Tilly.

Eclipsed by the glitzier version of Laclos' story, Dangerous Liaisons, the film fell flat, and, having moved to the wilds of British Columbia, he wondered if he would ever work again. If at times he seems to accept too much work with too little discrimination, it is not just financial acumen driving him, but the memories of those literal and figurative wilderness years. He wrote to Vancouver theatres explaining his track record, offering to do children's workshops, anything to stay connected to acting, but not one replied.

But that was then. This time around, his Vancouver sojourn shooting Hope Springs, with Minnie Driver and Heather Graham, was as leading man. Based on the novel New Cardiff by Charles Webb, who wrote The Graduate, it was recommended by Firth's great friend Nick Hornby, who saw him as the main character, Colin. Did it feel odd to be acting in his real name? 'A bit, especially when my real name is Mr Darcy,' he teases. The soppy, feelgood story concerns an English portrait artist who escapes from a broken London romance to Hope Springs, Vermont. 'I've never got on a plane and run away,' he says, 'but I've mentally gone to ground. I'm more comfortable being away when things come out, because I always have my doubts.' He was in South America when Pride and Prejudice appeared, getting bulletins from home about how he was the new housewives' choice and wondering if he dare return. Firth met Driver doing the Russian classic Chatsky at the Almeida Theatre in 1993. 'I credit myself with discovering her,' he claims mischievously, 'though she'd hate to hear that.'

She was 23 and he persuaded the director Pat O'Connor to see her for Circle of Friends, her early film break. Their bantering, jokily caustic rapport has not changed, and cuts through the syrupy romance of Hope Springs like a welcome shot of lemon juice.

Meeting up again with Rupert Everett for The Importance of Being Earnest was potentially a trickier proposition. Bar passing in the corridor on Shakespeare in Love, 18 years had elapsed since their mutual beginning, and Firth the neophyte had become the far bigger star. 'On Another Country I was terribly earnest and Rupert found me mind- numbingly dull. He described his memory of me as a 'ghastly guitar-playing redbrick socialist who was going to give his first half-million away to charity'.' Only the guitar, it seems, was an exaggeration.

Knowing the perils of dusty period pieces, he fretted about breathing new life into Earnest, described by its author, Oscar Wilde, as a 'delicate bubble of fancy', with this version released under the Ealing label, the first such event for 50 years. Actually, Parker's film is a sweet confection, with Firth suitably restrained as Jack, and the lovers' fantasies enacted in a magical rural space reminiscent of A Midsummer Night's Dream. It was in the context of an American press junket for it that Firth's headline-making comments about Tony Blair's illiterate England erupted. He shakes his head in mock despair. 'I don't think Mr Darcy is ever going to become Blair's cultural ambassador to the United States, do you?'

After hours of being told by journalists that England was a scholarly haven ('It must have been so hard,' they cooed, 'for Reese Witherspoon because all you guys all went to Oggsford...'), he finally cracked, replying that his compatriots rarely strolled around in tweeds quoting Shakespeare; in fact most of them didn't even understand it. 'I agree with Carol Vorderman—Shakespeare's as dull as ditchwater unless you're in the thick of it being done at its absolute best.'

But their misreading was telling. Firth, like Lord Olivier, has always been thought of as posher than he actually is. Another Country defined him and the careful enunciation that replaced his West Country accent has confirmed the impression. Not so. Firth was the eldest son of liberal academics, his father a lecturer in history and his mother in comparative religions, who raised their three children on books, conversation and no ITV on the telly. His younger brother, Jonathan, and sister, Kate, also went on to act—he works constantly if quietly; she played Hedda Gabler in Sheringham Rep before changing direction. They seem an independent clan, not in the least sugary about each other. Indeed, Firth couldn't remember where his father is teaching—though he seemed proud that exposure to his high- profile world had inspired his dad's social-sciences curriculum course on Masculinity in American Films.

As children they spent a year in Nigeria, where his parents, both from Methodist missionary stock, were teaching; another in St Louis, where he was disliked and isolated at school. Neither of these interludes helped Firth assimilate at his hated secondary modern in Winchester. 'I didn't want to grow up and wear a suit. I wanted to be rock'n'roll.' His first passion, at 10, was Marc Bolan performing Hot Love on Top of the Pops. 'When I analyse it now it was a sexual feeling I had for him. I loved that androgynous look, glitter and corkscrew hair.' He acquired a guitar, but the music lessons provided by his parents taught him to play Lord of the Dance and Kumbaya, so he gave up. 'If you'd told me at 16 that I'd be thought of as a posh person, I'd have said it was out of the question.' His escape was Saturday drama classes, and then a place at the Stanislavsky-inspired Drama Centre in London's Chalk Farm. He also thought he'd try for punky, gritty films; when Scum came out, he thought he should have been in it A tough nut, then? 'No, I was too wet to be one of them, but there were a lot of puny middle-class punks I could have been part of.'

Instead of low-life naturalism, he got famous in breeches. At first he was scared of Pride and Prejudice: popular television would put the purist in middle England's front parlour, expose him to both recognition and dislike. 'I want praise, but I never wanted universal recognition. You're recognised by people who don't adore you too.' He read Nick Hornby's High Fidelity around the time Pride and Prejudice was screened, as he was about to start filming Hornby's Fever Pitch. 'Even up to that point I had been really snooty about the mainstream. There's a character in the book who's in an avant-garde band; he's dreading that they've been booked to play at a party, but his impossibly pompous friend starts playing Twist and Shout, and it's such a relief. I feel the same. It was great to get off my high horse and entertain, and for the first time to have ordinary people say they really enjoyed it. I like Mr Darcy. Honestly! I'm a mainstream convert!'

As the movie offers roll in, the once-likely future of worthy, rigorous and unnoticed work recedes inexorably: he may do a play with a big 'star on stage' hoopla, but theatre will never be his world again. Does it matter? Though relaxed and cheery, I'm not sure that Firth is certain what he wants, other than to be bankable, admired, and look after his family. But on some latent level his tutor's warning against empty glamour has taken root. There are times, talking of shifting back to drama, when he looks frustrated, even wistful.

Discuss politics with him for five minutes and you see why. This is an old-style bleeding-heart liberal who campaigns for asylum seekers and tribal rights. He is even now scouring his Islington borough for a state school to which he might send Luca in the years to come. Placing him in the independent sector would bruise a principle, so researching comprehensives for a 14-month-old baby seems perfectly reasonable. If all efforts fail? 'He might end up going to school in Rome, and we might move there with him.' Firth stubbornly uses public health, though his son was born in Italy. 'My wife preferred to suffer in Italian,' he laughs, and then asks me not to quote that but, mea culpa, it's too cute to resist.

Firth says he has no ambitions, other than reaching that fantasy island of serious eminence and public adoration. Actually, he would quite like to disappear for 10 years and return as a grossly fat character actor. 'I want to use whatever happens to me; the parts are more interesting in middle age. I was frustrated playing dopey youths when I was 23, and if I envy any actor's physical attributes, it's Spencer Tracy and Gene Hackman, men with lines and whose faces imply so much.'

His next project, however, is 'more of the same' but with knobs on; Richard Curtis's directorial debut, Love Actually, will be fairy-light and full of laughs, and Bridget Jones's true love couldn't be happier to be part of the magic London circle again. It's got great lines, a heart of gold, and Emma and Hugh and Liam Neeson, he enthuses, absolutely irresistible. He plays a man who comes home to hear his girlfriend having sex with the bloke next door. 'Hurry up,' she orders, 'old pencil-dick will be back soon.' This makes him chuckle in anticipation of a big challenge. Presumably, it will be impossible to brood magnetically, or in any other way, at such a moment.