Martin Freeman is camera-shy. The impish actor is standing awkwardly in an old- fashioned hotel library flashing a non-smile towards a photographer.

"I wish I had that talent of being able to accept a photograph being taken," he says apologetically.

Almost 10 years since the role of Tim Canterbury in The Office made him famous, Martin still doesn't behave like a celebrity. You'll never catch him being papped at a nightclub or parading his two children in Hello! magazine.

"I don't like it when I see people do it. I don't think they should be put in prison or anything, I just think that it's not for me because I've never wanted to trade on anything else other than the work. I'd rather be at home."

Spotlight

Whether he likes it or not, Martin is now firmly back in the spotlight promoting Nativity!, his new film.

He plays frustrated actor- turned-primary teacher Mr Maddens, who is tasked with putting on the nativity play and beating the rival posh independent school to a five-star review in the local paper.

But, having been dumped by girlfriend Jennifer (Ashley Jensen) five years ago, Maddens hates Christmas. Struggling to cope with the nativity task, he accidentally boasts to his rival that his ex-girlfriend, now a hotshot producer in LA, is coming over to film the nativity play.

Ignoring the adage about never working with children and animals, Martin threw himself into the film, which is partially improvised and was conceived and directed by Debbie Isitt.

"I loved the idea. I'd worked with Debbie before on Confetti and we had a meeting back in December 2007 about her next idea -- she just described the outline of my character and his journey, and I was hooked."

Martin enjoyed the freedom of being able to improvise.

"Debbie's general MO would be, 'We need to get from this point to this point by the end of the scene -- away you go.' How you get there is down to you, but you have to hit certain landmarks along the way. I think Debbie likes the uncertainty of what can happen in a moment."

With more than 30 kids in most scenes there was plenty of uncertainty -- and Martin is convinced some of the children didn't even know he was an actor.

"For grown-ups it's easier to understand we've got other names that we call each other, but some of the younger children weren't sure if I was an actor or if I was their teacher. Some of them thought of me as Mr Maddens."

It's impossible not to ask Martin whether he ever starred in his own school nativity play as a child, but he insists he can't remember ever being in one.

"I was at a Catholic school so there would have been nativities happening. I remember a lot of Christmas stuff, a lot of mass and jollity, but I don't remember being in a nativity."

His own children are still too young to play Mary and Joseph -- Martin politely declines to give their names and ages -- but he's very keen to bring them up knowing the nativity story.

"Regardless of whether you're a believer and whether you dig it or not, this culture is where we come from, so it's just good to know stuff."

School

Martin grew up in the suburbs of London and attended the Central School of Speech and Drama. His acting career began on the stage, and he had roles in The Bill and This Life before The Office changed everything.

But he's adamant that there should never be a reunion of the award-winning sitcom, which ran for only two series.

"I think it would be a mistake, and I trust Ricky and Steve [Merchant] not to have to go back. Unless you've got a fantastic reason for doing something it always feels a bit like an admission of failure or desperation to me."

Nativity! is released in cinemas on Friday November 27

- Kate Whiting