Cillian Murphy might be scary on-screen but in real life his Irish charm shines through, writes Helen Barlow.

As Heath Ledger takes up Jack Nicholson's mantle to play a younger version of The Joker in the new Batman movie, The Dark Knight, he steps into the shoes of Irish actor Cillian Murphy who made his indelible mark as The Scarecrow in Batman Begins.

With his pale translucent blue eyes and chiselled cheeks, Murphy instilled terror in cinema-goers, and since his portrayal as the passenger from hell seated alongside Rachel McAdams in Red Eye, no one wants to sit next to him on a plane.

Or so the story goes.

"That's an advantage, I suppose," the lean boyish-looking 30-year-old responds with a smile.

The biggest acting name since Colin Farrell in Ireland and about as different from that actor as chalk is from cheese, Murphy is settled in his personal life but is far more adventurous in his movies.

He is being rewarded accordingly, having been placed No.3 on Entertainment Weekly's list of the most valuable players of last northern summer, while in January he received a Golden Globe nomination for his portrayal of a transvestite in Breakfast on Pluto.

During this interview, Murphy, married to installation artist Yvonne McGuinness, squeaks a rubber duck that has been given to him as a present for their baby son.

Later it emerges he was hung-over, having flown in some Dublin friends to his new film's Berlin Festival screening.

There is no doubt that like his fellow countrymen he retains a close relationship to literature and to the nature of drama.

Hailing from Cork, the London-based actor decided to return to Irish stories for his two vastly different upcoming movies, Neil Jordan's Breakfast on Pluto and Ken Loach's The Wind That Shakes The Barley, before teaming with his 28 Days Later... director Danny Boyle to make the sci-fi blockbuster Sunshine, due for release next year.

It had always been his dream to work with Jordan, and when Jordan produced Murphy's breakthrough film, Intermission, he had pushed the director to adapt Pat McCabe's novel for the screen.

Ultimately he couldn't resist as he had already forged a relationship with McCabe when he had made a film of his novel The Butcher Boy, a kind of companion piece which focused on a troubled Irish youth who resorts to violence.

Only here, rather than become violent, Murphy's daydreaming Patrick Kitten Brady (sic), the bastard son of a priest (Liam Neeson) disappears behind the veil of femininity.

Murphy used some fairly outrageous women's clothes for the film, which has been likened to Transamerica in its more humane twist on gender-bending. But, he says, it all came down to the story.

"A lot of the recent gay-themed movies, like Capote and Brokeback Mountain, were inspired by novels and I think that says a lot," he notes. "It's very healthy that in America these themes are being embraced."

He sandwiched the film between his two "bad guy" roles, so that the role represented a form of respite.

"Kitten has many prejudices and battles to overcome but her optimism is probably her engine that keeps her alive," he says. "It was refreshing to play somebody who is fundamentally good. I mean, all she wants is to be loved and to look pretty, and those needs are quite simple."

Did he try on his wife's underwear to get into the character?

"No I didn't," he responds with a cheesy grin. "You couldn't model it on your wife—that would be weird. I preferred to look at other women, just women in the Tube going around London.

"Women carry themselves differently; they have a lighter posture. I also hung out with transvestites and I met with one guy for a number of weeks. We went to clubs and he introduced me to his friends."

Murphy returned to his own roots for The Wind That Shakes the Barley. Loach's film proved so poignant that it overwhelmed the Cannes jurors who awarded it the prestigious Palme d'Or.

Murphy's heartfelt performance, which is at the centre of the film, belies the fact that he is a sensitive soul. He plays a medical student who is caught up in his country's struggle for independence and is at odds with his brother.

"Ken was shooting a film about the Irish Civil War and the War of Independence in Cork and he doesn't hire actors from outside where the story is set," he says.

"It was quite a magical experience because we didn't know the script, we were shooting in real time and with very little intellectual musing.

"A film has never been made about that period in Ireland, and still in that part of the country people won't talk about the Civil War because of the atrocities (committed by the British forces)."

The son of two schoolteachers, Murphy's success as an actor began with Danny Boyle's surprise zombie movie hit, 28 Days Later...

When Christopher Nolan cast him in Batman Begins, Hollywood took notice.

In Sunshine he returns to the future with Boyle. "The sun is dying so we have to fly a bomb at it to reignite it," he says.

Murphy co-stars with Australian actress Rose Byrne. And at least this time he is not cast as the bad guy.