HE’S posh, uncool and a little nerdy. In fact, comedian David Mitchell has long played on the comic image of lonely, dysfunctional loser.

He made his name as repressed, socially inept Mark Corrigan in Peep Show, the longest-running sitcom in Channel 4 history, which begins a new series in November co-starring his comedy partner Robert Webb.

In his autobiography Back Story, the witty panellist on QI, Would I Lie To You? and Have I Got News For You admits he’s never been much good with girls.

Until the penultimate chapter, that is, when readers will discover that the Cambridge graduate and star of That Mitchell And Webb Look is really an incurable romantic who fell hopelessly in love with writer and presenter Victoria Coren and waited three years for her to ditch her boyfriend before making his move.

“I’d never really had a long, meaningful relationship before,” he says.

“I had lots of friends who were serial monogamists and had a series of relationships, none of which was perfect, and I thought, that’s not for me. I don’t want to go out with someone who I’m not head over heels in love with. But then I met Victoria. It took us a while to get together, but I was smitten.”

They met in 2007 at a film premiere party and went out on a few dates, but then she dropped a bombshell when she emailed him to say she didn’t think the timing was right. She went on to find another boyfriend.

Mitchell went out and got drunk a lot.

“I didn’t tell my closest friends or my parents of the enormous sadness that overshadowed my life,” he writes.

Today, he laughs and says: “How did I feel? The word ‘bad’ springs to mind.

It was terrible, but at the same time I felt, you know what, I think it’s still going to happen.”

As his private life collapsed, his career went from strength to strength, with the sitcom, the sketch show and his appearances on panel shows.

Three years later, Coren, who is also a champion poker player, became single again and they started dating.

They got engaged in March when he popped the question in her kitchen and the announcement appeared in The Times newspaper. “She’s clever, funny, beautiful,” he says, beaming. “I think she’s amazing.”

They live together in her London flat and are tying the knot in November in London. Webb will be the best man.

Aside from wedding planning, Mitchell is currently promoting his memoir, which he wrote while sitting on a yoga ball due to a long-term back problem.

It takes readers on a walk across London (Mitchell finds relief for his back in walking) while he reminisces about his childhood, comedy career and other aspects of his life.

Born in Salisbury, Wiltshire, he is the son of a couple who ran a West Country pub in the 1970s and then moved to Oxford where they became lecturers in hotel management. The young Mitchell began to tread the boards at New College Prep School in Oxford, but never thought he had a talent for comedy.

“I remember thinking, I’m quite bright but I’m not funny. It was only when I was a teenager and got involved with the debating society at school that I realised that, while some boys were trying to make arguments, I’d be trying to make jokes.”

He failed to get into Oxford University, but was offered a place at Cambridge to study history, becoming president of Cambridge Footlights, where he met Robert Webb. The pair formed a double act which has lasted 20 years.

Mitchell struggled to make ends meet for some years after leaving university, hanging around in digs in London’s Swiss Cottage which he shared with friends.

He says now that Webb kept him going. The fact that there were two of them working together made it easier to stick it out. They began performing two-man shows at the Edinburgh Fringe and were then given the chance to write for Alexander Armstrong and Ben Miller.

But it was their multi-award-winning Peep Show which raised Mitchell and Webb’s profile to new heights.

In February, Mitchell and Webb will be appearing in a BBC Two comedy drama about diplomats called Our Men. But for now, his focus is on his personal life as his wedding day looms. And it’s clear what love means to him