Welsh wizard

He may be Mr Fantastic in Hollywood but Ioan Gruffudd knows he's got a lot to live up to. It hardly helps that you're automatically dubbed 'the next Richard Burton' simply for coming from the same country. He says he's been branded with that label and is well aware that following the likes of Burton and Sir Anthony Hopkins is no mean feat.

'Those guys are not only Welsh legends, they're legends of acting, so if I come anywhere near that I'd have had an amazing career.'

Now 34, the affable Cardiff-born star is heading in the right direction. This year saw him reprise his role as comic book hero Reed Richards - that's Mr Fantastic to you - for the sequel Fantastic Four: Rise of the Silver Surfer. Grossing US$286 million worldwide, in what was a crowded summer marketplace, it has cemented the Welshman's position as a major Hollywood player. 'It has transformed my career, being in this franchise,' he says. 'It's raised my profile immensely and opened so many doors. I don't think I would've got Amazing Grace had it not been for the success of Fantastic Four.'

Although far from a big-budget studio film, Amazing Grace sees Gruffudd play William Wilberforce, the 19th-century anti-slave trade pioneer who took on the British establishment with a stoic resolve to bring the practice to an end.

'I just loved the story,' he says. 'I've always been involved with period costume dramas, from the very beginning. But what's great about it is that they're such brilliant characters, either from life or literature, and it's a pleasure to play these parts. They reflect so well on me as an actor. I'm quite enjoying the fact that I'm carving a niche for myself as the go-to guy for heroic leading men.'

While this is true - most notably in the long-running maritime TV series Hornblower that first brought him to the attention of British audiences - Gruffudd was not cast in Amazing Grace for his ability to look good in period costume. 'As soon as I met him, I saw that soulfulness that he had in him,' says the film's veteran director Michael Apted. 'That sort of emotion that he had in him. It wouldn't do to have a Wilberforce that was kind of icy and cold.' And it didn't hurt, the director concedes, that The Fantastic Four had given Gruffudd some 'marquee credibility' which helped when financing the film. 'He was clearly the man for the job.'

Gruffudd admits that he knew very little about Wilberforce or the slave trade. 'I didn't cover it hardly at all in my history lessons,' he says.

'I didn't realise there was a big difference between the abolition of the slave trade and the abolition of slavery, which was 30 years later. I also didn't realise that Britain was sort of built on the back of slaves.' Fortunately he was given a crash course in English history by Apted, and read some 'extensive biographies' on Wilberforce.

'He was an extraordinary man to dedicate his entire life to this cause,' says the actor.

The role also required Gruffudd to sing the film's titular hymn - a task with which he acquits himself admirably.

'Being Welsh, we're very proud of our singing heritage,' he says with a laugh. 'But I'm sure they had [Welsh baritone] Bryn Terfel waiting in the wings just in case.' The film also had an effect on his father, a former deputy headmaster at Gruffudd's old school. 'We had a private screening. I was in America with them, and we went over to the Fox lot and they screened it there for me. And they were all very, very proud. It's a very tearful ending to the movie and the first time I'd ever really seen my father cry.'

This was a vast improvement on the last time Gruffudd showed his father one of his films. At the 2005 premiere of The Fantastic Four, 'he shook my hand and said, 'Yes, well done. Let's go and do something with a little bit more substance next time!'' It's understandable that Gruffudd senior was less than enamoured with a paper-thin comic book film (even if the Hollywood bean counters felt differently). Acting is in the family genes. Gruffudd's grandparents ran an amateur dramatics society, while his mother - also a teacher - liked to act in her spare time. 'But I'm the first one that's doing it professionally,' he says.

Gruffudd has done his family proud. After a spell in his teens on Welsh soap opera Pobol y Cwm he was snapped up by an agent in his final year of training at the prestigious Royal Academy of Dramatic Art. But while he immediately won a role in a short-lived remake of TV series Poldark, it was gently suggested to him that he might change his name (Welsh for John, it's pronounced 'Yo-an') to something more palatable.

'Agents in London, when I first started out, told me that I was going to get pigeonholed as a Welsh actor, and would only get Welsh parts,' he says. 'I don't want to work with those kinds of people if that's how narrow-minded they're going to be. I'm proud of who I am and the language that I speak.'

One need only look back on 1999's Welsh-language love story Solomon and Gaenor, in which Gruffudd played a young door-to-door salesman, to see this. By this point, he'd set the tone for his varied career to come. In 1997 alone, he went from appearing as one of the ship's officers in Titanic to appearing nude opposite Stephen Fry in Wilde. Yet after his subsequent success as Lieutenant Horatio Hornblower, as well as a turn as the original knight in shining armour Lancelot in King Arthur, suddenly he became tagged as 'the thinking woman's totty', as he cheekily acknowledges.

Inevitably, given his swarthy good looks (which recently led to him being employed as the new face for Burberry's fragrance for men), rumours spread that Gruffudd would replace Pierce Brosnan as James Bond.

'I did a magazine interview as Brosnan was doing his second Bond film, and he was on the cover and I did a spread inside,' Gruffudd recalls. 'The spread looked like a Bond thing - I was in a fancy car and they headlined it, 'Live and Let Dai'. Very clever. But literally the next day, there were bookies in Cardiff taking odds on me being the next James Bond.' He says he's quite happy not to have got the role. 'Daniel Craig has taken it to a whole other level. I wouldn't want to fill his shoes now.'

After relocating to Los Angeles, Gruffudd now lives there with his fiancee, actress Alice Evans, whom he met on the set of the sequel 102 Dalmatians. The pair have briefly worked together on Agent Crush, a forthcoming animated film, and Gruffudd admits he has no qualms about them appearing on screen together again. 'I think it would be great to work with Alice. It's all about being relaxed and having that chemistry,' he says. 'If you look at Burton and [Elizabeth] Taylor when they acted together, any relationship you have off camera informs any relationship you have on camera.'

Maybe he's ready for those comparisons after all. Amazing Grace opens on Thursday