Johnny Vegas: 'I never liked being the centre of attention'

How has Johnny Vegas done it? By "it", I mean transformed himself from a failed priest and potter to sought-after comic actor and much-loved household name. As he says himself, he's "no great shakes in the looks department" and first made his name as a stand-up who specialised in being bitter and drunk and bellowing insults at audiences.

Since then, almost imperceptibly, he has taken over our television screens, first playing the idiot savant role on Shooting Stars and then taking the lead in a series of sitcoms, among them Ideal, Dead Man Weds and Benidorm. There have been straight parts, most notably as Krook, all red-faced and menacing, in the BBC's adaptation of Bleak House, and in the film The Libertine alongside Johnny Depp. Oddly, what has really endeared him to the nation are the adverts – first for ITV Digital, latterly for PG Tips – in which he appears alongside a knitted monkey. These have proved so popular that strangers are always coming up to him and getting him to shout, "What's up, Monkey?", while they film him on their mobile phones.

So why him? "I think it's because the public want another George Best character," he muses in his familiar scorched rasp. "He was a lad done good who you could still sit in the pub with, and get drunk with." There's some truth in this, but I think there's more to it. I wonder if it's because he wears his heart on his sleeve, and his failures all over his face. On television, in whatever part he's playing, he exudes a certain sincerity and pathos. There is, apparently, no façade. With Vegas, what you see is what you get.

And what do we see? He's apparently lost some weight though he's still quite enormous, his top half almost a perfect egg shape. Where most actors look different – usually smaller and older – off screen, the Lancashire-born Vegas looks exactly the same. Sitting in a hotel bar in London, dressed in black jeans, T-shirt and baseball cap, you couldn't mistake him for anyone else.

He's here rehearsing for a show that will premiere at the Manchester International Festival next week. It's an ambitious piece called And Another Thing ..., about a trio of presenters on a television shopping channel looking to beat their all-time sales record. Vegas and his co-star, Emma Fryer, are writing it as they go along, "so for a lot of the time we're just standing in the middle of rehearsals going: "Er... What happens next?"

More alarming is that they've agreed with the real-life shopping channel Ideal World that they can broadcast live on television for 15 minutes in the middle of the play. So while the theatre audience will be able to watch the proceedings on the stage and on a screen, viewers of Ideal World will be startled to find Vegas hawking kitchen gadgets on their televisions.

The channel was wary of the idea at first, but warmed to it after Vegas assured them that they wouldn't make them look stupid. "When judging these things I always come back to Paul Whitehouse and those character-based comedy shows," he explains. "They're a piss-take but underneath there's a genuine love of the character. You're always looking for that little bit of humanity." Locating that thread of humanity was the aim of his early stand-up shows when he shambled on to the stage, full of lager and self-loathing. "You have a first impression of this person," he says. "And the longer you spend with him you realise that there's this very fragile ego underneath. For all the hot air, for all his ranting and raving, at the end of it, Johnny's just a needy man who wants to be loved."

Confusingly, he often talks about himself in the third person. He actually grew up as Michael Pennington; Vegas was the stand-up persona through which he first made his name, but who seems to have overtaken his former self. He thought for a while about dropping the stage name but realised that nobody would know who he was. Even his friends call him Johnny now, as does his wife – apart from when she's giving him a bollocking: "Then she calls me Michael. It's chilling. It stops you in your tracks".

He is in the middle of writing his autobiography, in which he tries to explain the evolution of Vegas. The process has prompted a few realisations about this dual identity. "I thought I always had a clear-cut view of where Michael ended and where Johnny started," he says forlornly. "Going back now, I'm seeing where Johnny came from. He may have started out as a character that I invented but there was more and more of me going into him, the less happy bits of my personality. He's not a monster, exactly, but he encapsulated a lot of the parts of me that I had buried from when I was growing up. Except, of course, you don't bury them, you just store them up. And there I was thinking I had control over it."

Part of the problem seems to be that people expected him to be like his stage character, and he couldn't resist playing along. The drinking didn't help. Vegas has always been known for his boozing. He insists he's a nice drunk, though he has frequently suffered lapses of memory, such as the time when he woke up in a hotel reception stark naked, surrounded by a huge contingent of stockbrokers who had gathered for their AGM.

At 11, he went to a boarding school seminary to train for the priesthood but returned, homesick, four terms later. "I asked to go, I desperately wanted to be a priest, but I didn't know what I was getting myself into," he recalls. After school came college – Vegas studied art and ceramics at Middlesex University, though he realised he was on a hiding to nothing when viewers at his end-of-year show mistook his female nudes for candlesticks.

Assorted short-term jobs followed: a stint in an Argos warehouse; selling boiler insurance door-to-door with his uncle; packing bottles of bathroom cleaner in a factory. He worked in a pub for years, where he felt immediately at home.

He first tried stand-up in his mid-twenties and knew he had finally found his calling. "It was the first time I felt the drive to do something and work at it, whether anything came of it or not." He still can't believe that his parents were so supportive. "They never tried to talk me out of things. I've been very lucky and very loved. I think they just hoped that I'd find my place."

Though he looks back at those early shows with enormous pride, he describes comedy as "the arena of the unwell. To want to get up and air your grievances in front of hundreds of people, there's something not right there." Vegas has now retired from stand-up, partly because it's hard to stay edgy when people want to see the bloke off the telly. But there was another problem, shrewdly observed by his friend Daryl: "He said 'Johnny, you can't do this anymore. You're too happy.' And it's true. I am."

This, he says, is down to his new family set-up. Vegas's 2002 marriage to Kitty Donnelly, with whom he has a seven-year-old son, Michael Jr, fell apart in 2004 and they finally divorced in 2008. Earlier this year Vegas married Maia Dunphy, a PR consultant. The pair divide their time between Dublin and his native St Helens.

Beyond the fact that he's a home owner with a mortgage, Vegas says his lifestyle isn't all that different to how it was 20 years ago – "I've never been somebody who would have five cars in the drive." In the school holidays he brings Michael up to St Helens. "We're bringing him up in northern conditions," he chuckles. "He mentioned Arsenal, so I decided it was time for an intervention."

Our time is officially up, though we carry on chatting into the evening – him on the vodka, me on the gin. He talks about his glory days at Edinburgh, when he won the Festival Critics' Award in 1997; and how he went to meet producers in America about a reality show, but they were so patronising he told them where to go. He also tells me, with a slight tear in his eye, about how his wife organised a surprise party for his 40th last year. It was the first birthday party he'd ever had. "I know it sounds strange," he says, almost conspiratorially. "But, you know, I never much liked being the centre of attention."

And Another Thing... is at the Pavilion Theatre, Albert Square, Manchester, 11-17 July. For tickets and information, visit mif.co.uk

Born Michael Joseph Pennington on 11 September 1971 in St Helens, Lancashire

Family Parents are Laurence and Patricia Pennington and he has two older brothers and an older sister. The family is Roman Catholic, although Vegas has now lapsed.

Education Attended St Joseph's College in Upholland, a Roman Catholic boarding-school seminary, but became homesick. Studied ceramic design at Middlesex University.

Career highs Has played Bottom in A Midsummer Night's Dream, and Krook in Bleak House.

In his own words: "It is easy for me to love myself, but for ladies to do it is another question altogether."