This actor's life: Andrew Lincoln is an altogether different animal in his latest stage role

Andrew Lincoln – cherubically curly, puppy dog-eyed love interest on British TV screens for the past decade – doesn't look quite himself today. His exuberant locks have been tamed, almost shaved off, he's wearing a lurid lime green and emerald golf sweater and is jangling some really quite nasty, cheap, yellowy gold jewellery. You'd never catch comfy old This Life favourite Egg, or classy, romantic Mark (who falls for his best friend's bride in Love Actually) in such an ostentatious rude-boy get-up.

Happily this disconcerting makeover is not a sign of early onset mid-life crisis (he's 35 years old) but part of the actor's assiduous preparations for his latest role in Parlour Song at London's Almeida Theatre. Lincoln plays Dale, car-wash magnate and man-about-town neighbour of the central married couple, Ned and Joy (played by Amanda Drew and Toby Jones). Dale is brash, a tad cocky and, as it turns out, a bit of a love rat – in short, the polar opposite of the notoriously cuckolded slacker Egg. "Totally! It's lovely for me to play a part that's not predatory exactly, but much more openly sexy," he says. "It's fantastically liberating, I much prefer doing something that's a bit more dangerous."

The play, by Jez Butterworth, who burst on to the theatre scene in 1995 with his debut, Mojo, has more than a hint of Pinter with its lyrical yet mercilessly precise use of language, dark comedy and suburban eeriness. The characters are all 40, and foremost amongst their various anxieties is the fear of ageing. Can Lincoln, one-time poster boy of the Nineties yuppie, relate to that? "I was on a set recently and realised that I've suddenly become the person that younger actors come to talk to. Oh God! I always thought I was the incendiary youngster and could get away with things, but it's changing."

Parlour Song is another new script for the actor who has made a habit of appearing in zeitgeist-defining premieres, including Joe Penhall's Blue/Orange at the National (with Bill Nighy and Chiwetel Ejiofor), Jonathan Harvey's Aids drama, Hushabye Mountain, and, most recently, Sam Shepard's The Late Henry Moss. Over the last decade, he has become the go-to guy for very modern, mildly flawed heroes, so it's surprising that he once dreamed of the greats. "My great friend Bill Nighy always says he's never going to wear tights. I'm not saying that, though there's part of me that does like to wear nice suits. When I was at drama school I wanted to do classical theatre. It just so happened that I did a film when I came out and I moved that way. I've been lucky to be able to bounce around and do lots of different things."

Luck and bouncing around notwithstanding, Lincoln, when pushed, admits that his success might also be down to a "driving engine of competitiveness" within. Born Andrew Clutterbuck (thank heavens for Equity and stage names) in Hull, he grew up in Bath, the younger son of a businessman and a psychiatric nurse. His older brother, Richard, now teaches RE in Surrey. "I was the freak," he laughs. When he was 14 years old, a teacher (the deliciously Dotheboys-sounding Mr Scrine) grabbed him off the rugby pitch to play the Artful Dodger. "And I loved it," recalls Lincoln. "It just caught me. I was kind of a loud, showy-offy child which is probably why he thought I'd blag it."

A summer with the National Youth Theatre scuppered a vague idea of becoming a vet and, as the acting bug took hold, he dropped one of his A-levels and concentrated on auditions. His father told him he would only be allowed to go to drama school if he received offers from five or more. "That was my father," shrugs Lincoln. "It was a very good thing, though because it really whittled out a burning desire in me." Having obediently gained places at the top five schools, he enrolled at Rada, paying his way with jobs as a commis chef, a barman and in one of his father's factories making car exhausts.

Within a year of graduating came This Life, the twentysomething house-share serial which captured a generation. "When I got the job I jumped up and down and whooped," he says. But he must get a tiny bit tired of talking about it? "I don't actually. It was a very remarkable job. It's good work. I never watch anything I'm in but I got a show reel together recently and got really sucked in. Everyone was brilliant and the writing was magnificent." Jack Davenport – naughty Miles – is still one of his best friends. But as the bunch of lawyers living and loving together defined Nineties television drama, so too has Egg, for better or worse, defined Lincoln for British directors, who have cast him variously as a boyish member of staff in Teachers and a thrusting young psychologist in Afterlife, while on the big screen he has popped up in Love Actually and Enduring Love. "I'd like to think that I've tried to do difficult things. Some may think I've been treading water for a bit, but I don't see it like that."

Wasn't it, though, an odd decision to revisit his most famous character for This Life +10, the special reunion episode in 2007 which, for many, soured memories of the zesty original with its smug Noughties tone. "It was good ... very strange. But very nice to see everyone again." Might it have been better to leave it in the 1990s? "I don't know what to say. I'd rather not talk about it, actually."

It's one of only two times that the otherwise talkative Lincoln clams up. The other is when he starts to talk about his one-year old daughter. He is guarded about his private life, mumbling that he finds fame "excruciating," having been "burned" in the past by over-exposure, most notably in rumours of an affair with Tara Fitzgerald during filming of The Woman in White. Two years ago, he married Gael Anderson – the daughter of Jethro Tull's Ian Anderson. They met when she was a runner and he was the director on a couple of episodes of Teachers (for which he earned a Bafta nomination). Chris Martin and Gwyneth Paltrow's daughter, Apple, was a flower girl at their wedding. They live in London but escape frequently to Cornwall where Lincoln indulges his surfing habit.

Family life is the one thing holding him back from pursuing a Hollywood career full tilt. He spent last year working on an NBC pilot in which he played a pugnacious young New York attorney. "They shut down Wall Street to film it. It really felt like I'd ramped up a level." He'd already had one close shave with Hollywood in the aftermath of Love Actually. "But I felt I was being groomed to be the new Grant and that's not what I wanted to do. Hugh is brilliant but my excitement at being over there was to play a whole myriad of American parts. Now I feel like I'm in a better space. It can be quite overwhelming there, you can be suffocated with praise. You think, 'Oh man, I'm gonna take LA down,' and then you don't hear anything."

Still, his next two roles should keep things ticking over. He plays Mike Collins in Moonshot, a film about the Apollo 11 landings for American television, and Edgar Linton in Wuthering Heights for ITV. On the first day of filming he was thrown off a horse but it will take more than that to dim his puppyish enthusiasm for acting. "What more could one want? One minute I was in space, then the next in breeches on a horse in Yorkshire. That's the glory of this job."

'Parlour Song', to 9 May, Almeida Theatre, London, N1 (020-7359 4404)