Daniel Craig has a reputation for being rather serious, a little sour even, but not today. Today, the craggily handsome actor who brought new life to the James Bond franchise in 2006's Casino Royale, is looking relaxed and smiling widely. But then, 2011 has been a good year for the 43-year-old.

He married the actress Rachel Weisz, lived out a childhood dream of donning spurs for the sci-fi western Cowboys And Aliens alongside Harrison Ford, and could finally confirm the news that millions were waiting to hear - that he's returning as 007 in the 23rd Bond movie Skyfall.

And this month sees him star in the hugely anticipated English-speaking adaptation of The Girl With Dragon Tattoo, a dark and violent thriller dubbed 'the feel-bad movie of Christmas'.

It's the first of the series, which includes The Girl Who Played With Fire and The Girl Who Kicked The Hornet's Nest, written by Stieg Larsson, a former journalist-turned-author who died before he could see his work become a worldwide success. So far, 65 million copies have been sold across the globe.

"Someone gave me a copy of the book on holiday and I read it in two days," says Craig, who plays Mikael Blomkvist, the Swedish journalist hired by retired tycoon Henrik Vanger (Christopher Plummer) to investigate the decades old disappearance of his niece Harriet.

"It's one of those books you just don't put down. There's this immediate feeling that bad things are going to happen."

From the start, Craig had an affinity for Blomkvist.

"I like his attitude. He's fighting the good fight, trying to uncover corruption and to be an influential journalist."

He pauses before adding: "If that's still possible."

While Blomkvist travels to a remote island on the frozen Swedish coast, an unusual and ingenious investigator called Lisbeth Salander (Rooney Mara) is hired to do a background check on him, a job that ultimately leads to her joining Blomkvist in his investigation.

A punk prodigy whose appearance warns people to stay away, Salander is a heroine unlike any other and Craig was instinctively drawn to her character.

"What's interesting about her is that even though she's a victim of sexual violence, she never psychologically becomes a victim," he observes. "Her strength and the way she can take a knock, get up and carry on is something I think people really hook into."

The film's directed by David Fincher, of The Social Network fame, a man whose reputation precedes him.

"David's very specific and... what's the nicest way to say it? Particular," the actor laughs. "But once you see the way he builds a scene brick by brick, it's an easy process to relax into. You give yourself over to it, knowing he's got his eye on all the important details."

Compared to Mara, who endured months of recalls, Craig was Fincher's favourite from the start.

There was one problem though. The actor was in the best shape of his life when he was cast, which wasn't suitable for a journalist who spends much of his time sitting at a desk.

"David told me to get fatter. It was a struggle, but I managed," he says with a laugh.

"I'm obsessive about getting fit. It's ridiculous, I'm over 40 now," he adds, before recalling Dame Judi Dench proffering two pints of Guinness and a pork pie once filming on Casino Royale had wrapped up and he could afford to relax a little.

Given he's currently shooting Skyfall, he's back in tip-top condition.

"I'm lucky enough to be given the chance to do a third Bond and it's my intention to make the best Bond movie; Bond with a capital B," says Craig.