If the name is not instantly familiar, perhaps the muscled torso is. Hailed as “the James Dean of ballet” by his internet fanzine, Will Kemp has a matinée-idol physique and has drawn attention in the cult choreographer Matthew Bourne’s productions, especially the all-male Swan Lake. More recently, a Gap television advertisement, in which Kemp “just ran and jumped about a bit”, brought his dance talents into our sitting rooms.

Until now, however, we have not heard him speak. All that is about to change, with Kemp’s big-screen debut in Van Helsing. He plays Prince Velkan, a lovely chap who becomes a werewolf and thus a target for the titular monster-killer. A perfectionist, Kemp responded first to the physical demands of the role, emerging bloodied and bruised. “Stephen Sommers, the director, would say, ‘What are you doing? Be careful.’ I would say, ‘Look, if you need to get this, let ’s get it.’”

The 26-year-old’s metamorphosis on screen mirrors, he hopes, his career. A couple of years ago, he quietly started taking acting classes. Immediately, there were offers from casting directors attracted by his good looks and star presence, but Kemp held back. “I knew I wanted to act, because creating characters is what I enjoy most,” he says. “But I told my agent, ‘Not yet. Let me do the workshops, learn as much as I can.’”

It was Kemp’s parents who first signed him up for dance classes, hoping that it might tease the introverted but intensely physical boy out of his shell. He is the eldest of three children, born in Watford. They were not allowed television and were encouraged to make their own entertainment. “I was always running around in costume, putting my brother and sister through their paces in front of the video camera,” he recalls.

The younger Kemp had a bad stutter — a trace of which still remains — which his parents felt might be helped by exposure to music and other children in a dance class. “Dance gave me a great sense of achievement early on,” he says. “It was very empowering.”

While Kemp is no Billy Elliot — he attended a Rudolph Steiner school — there were times when he had to stand up for himself. “I remember punching someone and not really wanting to. He was saying ‘you bloody poof’ — all that stuff. I don’t suppose it helped much in the long term, but he didn’t bother me again.” The rigorous training transformed him. “I began to look very different from all the other smelly teenagers,” he laughs. “Some were putting on weight, while I was getting lithe and stronger. That’s good with the girls.”

At 16, Kemp won a place at the Royal Ballet School. “Nobody thought I had a snowball in hell’s chance.” He recalls it being like the army: “Strict, tough, rewarding but frustrating.” In the final term he was cast as the Gypsy Lover in The Two Pigeons at the Royal Opera House. “After two years of struggle, struggle, struggle, it felt as if they were saying, ‘We’ve given you this part because you really can act.’”

In 1995, Kemp left the Royal Ballet to join Bourne’s Adventures in Motion Pictures, the youngest dancer in what was to become the award-winning Swan Lake. Within two years, he was playing the lead swan. “I was 21, and performing on Broadway — that was a big learning curve,” he says. “There was a lot of hype and lots of parties. I kept saying to myself, ‘Keep your cool, don’t get caught up in it all.’” Bourne and he have worked together on four productions over seven years: Swan Lake, Cinderella, The Car Man and Play Without Words. “He creates strong characters with a narrative.”

Kemp says his marriage to Gaby, a musician whom he met seven years ago, keeps him grounded. They married in 2002, and held a party at the Dorchester, where we meet for this interview. “It’s a bit of a special place for us, as you can imagine,” he smiles. Dressed in jeans and a loose-fitting dark shirt, Kemp is friendly and open — for now, able to move around London without attracting a second glance.

After Van Helsing, Kemp will return to the stage. In June, he will be reunited with fellow swan Adam Cooper in a William Tuckett- choreographed version of Stravinsky’s The Soldier’s Tale. Later in the year, he will be on cinema screens again, in Renny Harlin’s Mindhunters, a thriller in which he plays one of a group of FBI rookies who are murdered one by one by a killer in their midst. “Mindhunters was my first film,” he says. “I was green beyond green, new to it all. I learnt a lot.”

Van Helsing was far more enjoyable, he says, and seems more likely to be his Hollywood calling card. “It’s funny, but the Gap ads did open doors with the studios,” he laughs. “People certainly knew who I was.” The chances are that millions more will soon.