Ben Barnes was responsible for making Chronicles of Narnia: Prince Caspian a huge success in the title role.
He is reprising the character as the king in the third movie, The Voyage of the Dawn Treader.
While Dorian Gray is the first grown-up Barnes, 28, has got to play, he also had to add another 20 years to his age, as the character ages, even if his face remains youthful. "I was a bit scared of doing the scenes where I'm older but I ended up enjoying them the most," Barnes says.
"Now having seen the movie those were the scenes that I found most convincing, ironically."
Based on Oscar Wilde's Victorian novella, The Picture of Dorian Gray, the film tells of a young man's sudden ascent into high society after receiving an inheritance.
He falls in love with Sybil Vane (Rachel Hurd-Wood) but, under the influence of Lord Wotton (Colin Firth), discards her to pursue a hedonistic lifestyle. When Basil Hallward (Ben Chaplin) paints his portrait Dorian realises he wants to retain his current beauty and makes a pact with the devil to make it happen.
The film now allows Barnes to stake his claim in the adult realm.
"It's lovely to have another movie star around who's got range and charisma, especially in the UK," says the film's director Oliver Parker, making his third Oscar Wilde adaptation after An Ideal Husband and The Importance of Being Earnest.
"There's just something about Ben. At first I was concerned there was not enough meat on the bone, that slightly pretty boy look, but actually I've been delighted working with him, seeing how far he's prepared to push himself."
The film's producer Barnaby Thompson had worked with Barnes on Australian director Stephan Elliott's Easy Virtue, and suggested him as Dorian. Colin
Firth also appeared in that film so there was a playful one-upmanship going on between the two actors on the Dorian Gray set.
"Colin, he's wonderful, but he's not a very good mentor," Barnes says with a chuckle, "because you ask him a question and he says, 'Just deal with it, get on with it'. And then he goes around telling everyone what a great mentor he is to me. But I can learn so much by watching him and he's such a funny man, too."
Tall and handsome, with piercing brown eyes, Barnes is poised to be Britain's new romantic idol. He is trying to deflect a lot of the attention though.
"I honestly am trying not to think about it too much or worry about it too much, because you're only presented with the opportunities that are in front of you at any given time and those are the only choices given for me to make."
Interestingly Barnes made a huge call when he left the West End stage production of The History Boys to play Prince Caspian in the second Narnia film.
The film proved a hit and now he is shooting the third film in the billion-dollar franchise on the Gold Coast in Queensland.
"I'm actually loving shooting this film there. The studios are incredible. We're doing a lot more in the studio this time. We've also been filming at Cleveland Point, where they built the boat," he says.
Now Barnes is keen for a change.
"I'm after variety really. Having worked on a few fantasy things, and obviously Dorian Gray is slightly darker material, I was in Boston recently shooting a movie called Locked In where I play a young dad who gets in a car crash with his daughter and he's trying to piece his life back together. She's left in this locked-in state and it's a sort of a fractured structure Memento-style original script.
"So that was something contemporary, just really, really different."
