Interviewing Ricky Gervais feels more like my own private stand-up show than just an opportunity to quiz The Office star about his latest Hollywood outing. I've barely walked into his Soho hotel room and he's cracking jokes about the fruit on the table between us.

"I love a banana," he says with a smirk, before bursting out into peals of laughter. "It's got its own little carrying case. It's the most filling of fruits."

Indeed, the 48-year-old, who is clad in his trademark black T-shirt and jeans, drops more one-liners during my half-hour chat with him than he does during the whole 90-minute length of his upcoming movie The Invention of Lying (released November 26).

But the film, which the Reading-born comedian co-wrote and co-directed with Matthew Robinson, places more emphasis on melodrama than it does on gags and skits.

Like his big-screen acting debut, the David Koepp-scripted Ghost Town, it finds him once again venturing into the other-worldly realm of genre fiction. However, Gervais insists he is no fan of science fiction and fantasy.

"I see these high-concept films as analogy and metaphor and as a vehicle to explore real emotions," he says. "Ghost Town was about making a man see that he was in the wrong life. That was the important thing - not whether there were ghosts or not.

"Just like how It's a Wonderful Life is about making a man see how lucky he is, not the fact that there's an angel in it. I don't believe in angels but it enhances the film."

Set in an alternate reality where nobody has told an untruth until Gervais' character Mark Bellison inadvertently lets a little fib slip, The Invention of Lying brings to mind Frank Capra's 1946 all-time classic.

"It's A Wonderful Life is one of my favourite films," says Gervais. "[Director] Billy Wilder is another of my heroes and my character is a little bit like Jack Lemmon in The Apartment.

"We wanted to create a kind of other-world. We didn't want people to go 'that's so 2008' so we've gone back to the 40s, 50s and 60s, while some of the technology is kind of 80s or even 50s futuristic, which creates a slightly surreal feel.

"That was a conscious decision. One of our remits for making it was that we wanted to make the best episode of The Twilight Zone ever and then have the comedy and the romance on top of it."

Initially, the previously luckless Bellison uses his newfound gift for personal gain. He rises to the top of his documentary-scripting company and courts the glamorous Anna McDoogles (Jennifer Garner), who had previously dismissed him because of his inferior genes. However, after reassuring his terminally ill mother about the existence of an afterlife, he inadvertently becomes a very reluctant messiah.

"Who wouldn't do that?" ponders Gervais. "My mother was dying for about a year and if I could have said: 'yes there's a God', I would have said so. I would have lied because religion is such a lovely lie. But you are what you are.

"I was brought up to believe in God and my mum sent me to Sunday school. When you grow up on a working-class estate and money is tight, opportunities are smaller because you're a working-class mum who doesn't believe her son is going to grow up to be a millionaire or a surgeon.

"You just want him not to do drugs and not to go to jail for murder. They think that if you believe in God, he will keep you out of trouble. To a working-class mum, Jesus is like an unpaid babysitter."

However, The Invention of Lying is more of a gentle satire than some of the savage rants on religion that Gervais has delivered in the past. "I hope that people will like this whether they believe in God or not," he says.

"This isn't an atheist rant, it isn't propaganda. I want people who believe in God to love this film. They can see it how they want to, but it's also nothing to do with religion or spirituality. It takes place in a parallel world where certainly things didn't exist and this is its genesis, no pun intended."

Gervais claims he wasn't daunted by the transition from small screen to big screen. "It was quite seamless and it wasn't like I was moving away to do something completely different," he says. "But if it had been The Matrix I wouldn't have done it. I know what I'm doing with this.

"It's a relatively small film and I had total control over it. There weren't any CGI shots, it was about human relationships, which I have made my area of study since watching people growing up and making people laugh. The Office was purely a study of human behaviour and body language and this was a logical extension of that."

Gervais' recent absence from British television has left a vacuum, which has been partially filled by New Zealand's Flight of the Conchords. The series has garnered a large cult following, which includes Gervais.

"It's a lovely show," he says. "I love them because of their sweetness. If they were cocky, it wouldn't matter if they had all the jokes in the world. They're two loveable losers.

"They don't have to even open their mouths. I just love their facial expressions. Add to that how clever they are and they're world-beaters. I love them for all those reasons. They tick every box."

There is a similarity between David Brent and Rhys Darby's hapless but lovable band manager, Murray Hewitt.

However, Gervais believes the character's lineage can be traced back much further than that. "The middle-aged man with a blind spot is a comedy staple in Britain," he says.

"We're laughing with him and not just at him because of the difference in how he sees himself and how the world sees him. He's no different from Captain Mainwaring [of 70s classic Dad's Army] in that sense."

Gervais' current workload indicates that he has no plans to return to television in a hurry. Cemetery Junction, his first cinematic collaboration with The Office and Extras co-creator Stephen Merchant, is due for release early next year.

An animated movie of his children's book series Flanimals is also in the pipeline, while a cartoon adaptation of his infamous podcasts with Merchant and cult comic Karl Pilkington has just gone into development.

"I'm more excited about that than Flanimals and The Invention of Lying," he declares. "It's amazing how they've animated all those ridiculous conversations.

"Karl is going to be the new Homer Simpson but he's real, you can meet him. Little things like that are labours of love. I did Flanimals to make my nephew laugh and I did the podcasts to be in a room with Karl Pilkington. If you do something with a laugh, it will be okay."

* The Invention Of Lying is out in cinemas November 26. Ghost Town is out now on DVD.