Ioan Gruffudd: Enter the dragon

With 'Fantastic Four', Ioan Gruffudd has arrived as Hollywood's new, Welsh superhero. He tells Liz Hoggard why one day people may even be able to pronounce his name

Fantastic Four, the adaptation of the Marvel comic books, should vindicate Gruffudd's move to LA three years ago. Things went a little quiet for the actor once dubbed "one of the 30 most interesting people in the world right now" by Time magazine. He was offered the lead in last year's futuristic legal drama from CBS, Century City, but the show was pulled after just four episodes, much to the glee of some British critics who seemed to take it personally that, after a run of hit British TV series – Hornblower (1998-2001), Great Expectations (1999), The Forsyte Saga (2002) – Gruffudd escaped without doing the requisite edgy British films and serious theatre. But he held his nerve, and Fantastic Four, with Jessica Alba and Nip/Tuck's Julian McMahon, should catapult him into the A-list. "Century City was short-lived," he admits, "but it gave me the opportunity to speak in American every day for five months. It was a great exercise, getting new muscles working."

Gruffudd is a seriously nice man. Driven, yes, but boundlessly enthusiastic and polite. This he puts down to his teacher parents – he went to the comprehensive where his father was headmaster. There is a nice Puritan streak to Gruffudd. You sense he is embarrassed that everyone harps on about his five-minute role as the officer who rescues Kate Winslet in Titanic. He's done more interesting work since, from the Oscar-nominated, Welsh-language Solomon and Gaenor to Tony Marchant's masterful reworking of Great Expectations, in which he brilliantly conveyed the egotism of youth.

One of three children, he was born in Cardiff, where his grandparents ran the local amateur drama society. He became an accomplished oboist and singer then, at 13, a professional actor with a role in the Welsh soap opera Pobol Y Cwm ("People of the Valley"). At 18 he went to Rada full of confidence, but the experience was bruising. "I was quite a late starter," he admits. "As a teacher's child I found that automatic respect for authority wasn't necessarily a good thing. My philosophy was all about pleasing everyone and getting it right, rather than challenging and asking questions. It's only now I'm getting the confidence to do that because, in America, they're not scared as a nation to ask questions and have a really heated debate."

Several times, he nearly dropped out of Rada. After quite a religious, Christian upbringing, then lonely and adrift in London, he joined a quasi-religious cult. "I hadn't been going to chapel," he says. "A guy stopped me in the street and asked if I would like to go to church. I thought it was a sign." He found himself at a "brilliant service" that led to Bible studies. "I knew it wasn't right but I didn't feel that it was so wrong, so other-worldly – that's how convincing the whole thing was. In the end my mum had to come up to London to sort my head out." The turning point came in his final year at Rada, when, after three years of being given only the smallest parts, he was cast as George Tesman in Hedda Gabler. He was spotted and landed the lead in a TV remake of Poldark.

He made his film debut in 1997, playing one of Oscar Wilde's lovers in Wilde ("my first silver-screen kiss"). The same year he was offered Titanic. By all accounts it was an explosive experience working with James Cameron. "We were working with a very obsessed director who found it hard to ... delegate. I was crying in the make-up chair f every night for a week when I arrived. Not because I'd been shouted at, but because of the atmosphere." He bonded with Winslet and DiCaprio, whom he admits became a role model.

In 1998, Gruffudd was offered Hornblower, adapted from C S Forester's novels. It was wet-breeches TV. Elderly ladies set up fanclubs for him, and he once served a delegation of American fans cups of tea when they turned up at his flat late one evening. "I did think, where are my young, cool 20- to-30-year-old fans?"

Hornblower won an Emmy in the States and brought Gruffudd to Hollywood's attention. He was in Black Hawk Dawn, then producer Jerry Bruckheimer snapped him up for King Arthur. While the film was a bit of a medieval potboiler, Gruffudd acquitted himself well as Launcelot. His matinée looks obscured by a straggly beard, he is more warrior than lover. "I'm glad you say that," he enthuses. "In the past I have felt slightly pigeonholed with the success of roles like Hornblower, all ruffled shirts and wonderful costumes. I think Launcelot was the turning point because he's more masculine, more dangerous, which goes hand in hand with me growing older. I want longevity, so I'm always trying to escape the way I'm perceived – you know, Ioan the soft-spoken Welshman."

And now there's Fantastic Four. The film follows four friends who become a superhero team after exposure to cosmic radiation. Gruffudd plays Reed Richards (aka Mr Fantastic), the geeky inventor who can stretch his body as thin as an elastic band. "There's something amazing about relinquishing half your character to these visual effects people, having to trust them to manipulate you so you look good and strong and masculine."

I ask if it will tackle some of the more complex issues thrown up by recent superhero movies, such as racism and disability (X-Men) and the crisis of modern masculinity (Spider-Man 2). Gruffudd answers carefully. "It's a very pure story in that sense." The phrase is often a Hollywood euphemism for no-brainer, but there's no denying his enthusiasm. "It's a really simple, fun-entertainment film. The best thing from the comic-book perspective is that they are normal people; they aren't mutants to begin with. Our superpowers are thrust upon us."

So is he ready for international stardom? "As an actor, you have to admit you are a show-off. But with so many magazines like Heat, it's diminishing the mystery of going to see somebody on the big screen. The less you know about somebody the better."

Gruffudd can be a very cerebral actor. You sense real emotional intelligence. Yet the King Arthur publicity dubbed him "Launcelot, the chick magnet". In the flesh, he is ridiculously beautiful, with Mediterranean colouring and chiselled features. There's something about Hollywood grooming that makes men (cf Clooney and Pitt) look like honourary girls. But Gruffudd says he is only medium-vain. "Being attractive, it's not something I do consciously," he has said. "It's incredibly flattering that people think I appeal to women. But that was a gift from my parents. My acting, my personality – that's what it's about."

Does he ever tire of the gush? "I don't think I could ever get exhausted, to be honest; it's incredibly flattering. You have to try to look at yourself objectively, without sounding too vain, to realise what your strengths are and what people are responding to. If that's one of the elements, then great."

He thinks LA has cured him of shyness. "There's a physicality and confidence to Americans; they're very present. That's something I enjoy being around because it rubs off on you. Although an actor friend of mine visited recently and said, 'It's no wonder they write such terrible scripts these days, there's no pain! Everything's so nice you can't be bothered.'" He lives in West Hollywood in a little Spanish house with his girlfriend of five years, Alice Evans. "I love driving round everywhere and every time you go to the supermarket, it's as if they've newly stocked it for your visit. I love the outdoor, fresh-air lifestyle, the vastness of the area. I haven't missed London or Cardiff at all."

He met Evans on 102 Dalmatians, although they didn't get together immediately (Evans was in a relationship with Olivier Picasso, the grandson of the painter). Recently there have been rumours in the press that the relationship is rocky, but his face lights up when he mentions her. "She's an amazing woman. Because she lived in Paris and hadn't gone through that whole Rada training, it was so refreshing when I met her. She's very direct, honest and open." I mention that when I interviewed her, I found her nothing like her It-girl image. "I know, she suffers from that perception," he says. "She's allowed to be shy and retiring and nervous like everyone else, but when people see her looking fantastic in a photograph or at the Baftas, it's deceptive."

He has no time for actors who say wealth and integrity don't mix. "As long as you understand that you find happiness through family, friends and love, then money is just a nice bonus." Last year he fronted a Welsh NSPCC TV campaign against child abuse (still a difficult topic in Wales). As his best friend, and fellow Welsh actor, Matthew Rhys puts it, "The danger is I'll sound sycophantic but he's got a lot of good characteristics and it's hard to separate his best. He's nice. It sounds crap but he is. He has the most open, generous personality and is honest. Immense loyalty as well."

And modest. Gruffudd is the first to admit his estuary accent in BBC1's Man And Boy was a mistake. "It was my harshest criticism to date, but as an actor myself I could hear it wasn't a perfect representation. It has driven me on to work so much harder on accents. They say the most successful people are the ones who have failed more than they have succeeded."

One worries Gruffudd may be seduced by Hollywood (he has turned down major roles at the National and RSC) but he understands that if you make a name, "you have the power to get big juicy theatre parts, though the longer I put it off, the more terrifying it would be to step on stage. I don't have a strong desire to play Hamlet. But I'd love to work with someone like Michael Grandage. I love the intimacy of places like the Donmar and the Almeida."

There are the inevitable Bond rumours, but I'd like to see him do more gritty contemporary work – as he did in Peter Kosminsky's Warriors, playing a UN peacekeeper sent to Bosnia. He prepared by meeting people from both sides of the ethnic divide. "I wanted to be involved because I was so ignorant of what went on. In the early Nineties I was being totally self-obsessed at Rada."

Last year, Gruffudd was honoured by his countrymen for his commitment to retaining Welsh identity – and telling the world that Wales is not in England. In fact he confesses he is a little less militant these days. "I was probably doing more to pigeonhole myself as a Welshman and a Welsh actor than anyone else! A lot of the stuff I said in the past sounded defensive – a young man's ideals about who I am and where I'm from. I realise I don't have to force that on people, but just use it as a safety net, to stride out into the world knowing that I have a strong sense of identity. Because we're all landlocked in this nation together and we should be celebrating it."

'Fantastic Four' is released 22 July