Ricky Gervais is wearing what can only be described as comedy spectacles and a comedy wig. As Andy Millman in the new series of Extras, the acclaimed sitcom which returns to BBC2 next Thursday, he is sporting a pair of glasses of an enormity rarely seen outside Sir Elton John's eyewear collection and a synthetic bubble-perm apparently borrowed from Harry Enfield's Scousers. But there is a reason for Andy making himself such a figure of fun.
When we are reacquainted with him at the start of the new series, after years of toiling away in obscurity as a film and TV extra, he is finally on the verge of his big break. His sitcom, When the Whistle Blows, about the rib-tickling goings on at a stereotypical northern brush factory, has been green-lit by the BBC and - even better news - Andy has landed the lead role. He is playing foreman Ray Stokes - hence the aforementioned accoutrements.
But (and because this is the comedy of disappointment, you just knew there would be a "but", didn't you?) even though Andy has been given what he has always dreamt of, he is still deeply dissatisfied.
In order to get his sitcom on screen, he has had to swallow his pride and his principles. He has had to trade in his ideals about creating a classy, credible comedy "that stands the test of time" for an utterly predictable lowest-common-denominator show. Andy has sacrificed integrity for celebrity.
Before he delivers his catchphrase as Ray - the deathless line "You're having a laugh" - Andy peers out from the stage at the howling people in the studio audience. A shadow of pain darkens his face as he clocks the legend on their T-shirts: "I'm a lady", "Am I bovvered?", "Garlic bread" and "It's Chico time!" It suddenly dawns on Andy that he's died and gone to catchphrase hell.
The set of Extras is on a cavernous sound-stage at Pinewood Studios, home of the James Bond movies, sandwiched between Goldfinger Avenue and Broccoli Road. In a pause between scenes, Gervais bounds over to meet me.
Gesturing at his wig and specs, the co-creator of the ground-breaking, genre-defining, multi-award-winning sitcom The Office pre-empts any comments about the ludicrousness of his appearance by saying: "As you can see, this is another naturalistic comedy. I'm getting this sort of sitcom out of my system, so I don't have to bother with the real thing now."
His co-writer and co-director Stephen Merchant politely interrupts and coaxes the gregarious Gervais back on set. In this scene, Andy is trying to justify to his best friend and fellow supporting artist, the delightfully idiotic Maggie (Ashley Jensen), just why he has sold his soul to get his sitcom made.
"Everything sorted?" Maggie asks sympathetically.
"Oh, yeah, yeah," blusters Andy, the uncertainty evident in his hesitant tone. "Had to kick arse, but it's all been sorted. All this stuff about, 'Is it good, is it bad?'... It's good if it's pleasing people. Comedy for me is about making it as broad as possible, so that everyone can enjoy it.
"I want three- and four-year-olds to enjoy it, all the family. Bring as much joy to the world as you can. So yeah, I'm going to make people happy. Definitely," he adds, his voice trailing away unconvincingly.
As Maggie goes off to take her seat in the audience, she leaves Andy with his head bowed, sighing heavily. He is a picture of self-loathing. That's what distinguishes the work of Gervais and Merchant: it's less sitcom than sadcom.
But Gervais, an exuberant presence on set, never lets the atmosphere get too downbeat during filming. So when Merchant shouts, "Cut! That's great, Ricky," at the end of that poignant scene, Gervais pipes up: "That wasn't acting, you know. Just before I went on, someone said I looked like Russell Grant, so I was genuinely, genuinely depressed!"
He and Merchant are on equally good form, a little later, in Merchant's dressing room. The stocky Gervais is still dressed in his icky, factory-foreman's tie and shiny white nylon shirt with the name-tag "Ray" pinned to the chest pocket. The unfeasibly tall Merchant, meanwhile, is in the seriously naff red polo-neck jumper worn by his character, Andy's hopeless and venal agent.
The pair are as astute, self-aware and ironic as their fictional alter egos are dense, self-deluded and dim. The banter flies across the room as quickly as a ping-pong ball hit by two highly skilled players.
As they finish each other's sentences and top each other's gags in the manner of a seasoned double act, the chemistry between them is obvious. The radio station Xfm has capitalised on this rare comedy symbiosis, employing them to co-host a show.
They may look like the odd couple - an extreme and far funnier version of Little and Large, perhaps - but if there's a more accomplished comedy team currently at work in Britain, they've yet to be discovered.
It's Britain's celebrity-obsessed culture that provides the backdrop to Extras. Andy thinks that if only he can be famous, then all the other problems in his life will miraculously be sorted. Of course, attaining a smidgen of celebrity has the opposite effect and only serves to make him feel more unfulfilled. The moral of the story is: be careful what you wish for.
Gervais remarks that: "Andy gets to peek behind the curtain at the lives of the famous, but is sorely disappointed to find that his life remains exactly the same. It's about people who are always unhappy with their lot. They crave something different, but once they enter the magical land of fame, they realise that absolutely nothing's changed.
"Andy is disappointed because fame does not give him what he was promised. Now he's a little bit famous, why isn't the phone ringing all the time? And why isn't he at the top of the pile?
"You can never be famous enough. As soon as you get it, you start looking at other people and thinking, 'His is bigger than mine - it's not fair.' That's what Andy thinks. It was the same set-up in The Office - you're always disgruntled that someone has got a bigger chair than you."
The creators of Extras have tapped into a rich social seam here. "Fame is pointless and unsatisfactory by itself," Gervais reckons. "Fame without respect or self-esteem is infamy.
"I remember being on the red carpet at my first Baftas. I'd made it overnight and a journalist asked: 'What advice would you give to someone who wants to be famous overnight?' I replied, 'Go out and kill a prostitute.' There is no difference between fame and infamy."
Gervais continues: "People should realise lots of bad fame doesn't make good fame. But they think, 'People don't like me, but if I do one more reality TV show to show my good side, then they'll love me.' But they don't - they just take the piss. All celebrity autobiographies should be called Love Me or I'll Kill Myself! Why would you want to live your life like an open wound?"
He goes on to reveal a truly shocking statistic. "A recent university survey of 10-year-olds asked, 'What do you want to be when you grow up?' The majority said 'famous'_ - not even 'pop star' or 'actor'.
"Some people are so desperate for fame, they buy every publication every day, and if they're in two papers on a Monday, they have to be in three papers on the Tuesday and four on the Wednesday. It's like a drug.
"Fame is getting more and more sought-after - even though everybody knows Andy Warhol's line about everyone being famous for 15 minutes. They've seen how fame eats you up, but people just don't learn that lesson. They think, 'I'll be different'."
Genetically programmed to exploit every possible gag opportunity, the Bristol-born Merchant expands on Warhol's famous statement. "In fact, he was wrong. Now people only have 10 minutes of fame. That's just long enough to call an agent who lives above a betting shop in Ealing, who looks after someone who didn't win Big Brother 2 and his brother-in-law, a DJ and part-time Ali G impersonator."
When it comes to celebrity, Gervais and Merchant know whereof they speak. Gervais views it as an occupational hazard, the one downside of doing a job about which he is passionate. He recently said that he never takes a holiday because he enjoys working too much.
The irksome part of being high-profile first struck him a couple of years ago when he was browsing through the underwear department of a local store near the central London home he shares with his long-term partner, TV producer Jane Fallon.
"It's strange having people watch you buy pants," Gervais smiles at the sheer bizarreness of it. "I don't like being recognised much and I always feel a bit self-conscious. So I walk a little bit faster down Oxford Street and wear a baseball cap. I don't go on the Tube after hours or to after-show parties. If there's one thing worse than members of the public coming up to talk to me at parties, it's actors from terrible shows like... No, I won't mention any names!
"When they're standing there chatting to me, they are clearly loving it so much more than I am. I try to be polite, but I'm thinking 'I don't respect your work in the slightest.' What am I supposed to say to them? 'Bring me your ideas - I'm just dying to work with you'? 'Let's go skiing together'?"
But, fascinating and topical subject though it undoubtedly is, Extras is much more than a meditation on the pernicious effects of fame. Frequently playing with tone and dancing with thematic partners not readily associated with post-alternative comedy (racism and homophobia, for instance) the series works on several other levels, too.
It adheres, for example, to the first rule of British sitcom: failure is funny. We love a loser.
The more comic characters strive for success, the more they are doomed to founder. Like all the great domestic comedy figures, including Gervais' most celebrated creation, the woefully and wonderfully misguided David Brent, Andy is trapped by his own weaknesses and crippled by awkwardness and embarrassment.
"One of our bugbears," Merchant reflects, "is the stand-up who thinks he's cool and above the audience. What he's actually saying is: 'This is why I'm better than you.' Why should we laugh at this man who has a great life? We don't want to listen to people telling us what a great holiday they had. That's not funny or interesting. Where's the vulnerability?"
Gervais chips in that "you want someone stumbling on stage and telling you his life is shit. You can admire cool comedians, but you can't love them or hug them like we want to hug Oliver Hardy or Johnny Vegas. Comic characters should be precarious.
"You care about Stan and Ollie because you want to stop them falling backwards off that wall. In the same way, you can't help warming to Woody Allen when he asks a girl, 'What are you doing on Saturday night?' 'Committing suicide.' 'What about Friday?' He's so desperate, he'll make do with someone who wants to kill herself!"
The other element that sets Extras apart, of course, is its employment of real-life stars playing twisted versions of themselves. For this series, Gervais and Merchant have persuaded such high-profile names as David Bowie, Chris Martin, Sir Ian McKellen, Jonathan Ross, Robert Lindsay, Stephen Fry and Daniel Radcliffe to send themselves up.
In the first episode, Orlando Bloom bravely takes the rise out of his image as one of the world's most swoon-inducing heart-throbs. Displaying a commendable willingness to lampoon himself, this Bloom is vanity on legs.
The gag is that Maggie, who previously showed herself comically eager to date anyone with a pulse, spurns his advances. Increasingly frustrated, he tries to win her over by planting his most passionate kiss on her lips. When he steps back, however, she looks distinctly non-plussed, shrugging: "Not really my cup of tea."
Gervais says that Bloom was a tremendously good sport. "We needed the biggest 30-year-old heart-throb in the world because the joke is that he falls for Maggie and it's the one time she's not interested. Orlando was great - he wanted to make the character really desperate.
"He totally sends himself up. In real life, he doesn't go around worrying about polls of the most handsome actors in the world. He knows that if you want any longevity in this business, the last thing you want to be known as is pretty."
Gervais, 45, and Merchant, 31, say that they use the celebs in Extras not as an ostentatious "look at me" calling-card, but as a means of furthering the plot. They all perform the function of highlighting Andy and Maggie's innate absurdity.
"They are a device," Merchant explains. "This is not a sketch for Comic Relief where they can just turn up, do their thing and leave. They have to advance the plot and be comic foils for Andy to react to as a straight man. It can't be just like them popping up on a panel game and doing their schtick."
So the effortless superstar David Bowie acts as a counterpoint to Andy's very minor celebrity, while Jonathan Ross points up Andy's eagerness to hang about with his new showbiz best mates.
Sir Ian McKellen is also used to throw Andy's inadequacies into relief. Gervais reveals that "in his pursuit of artistic credibility, Andy gets the opportunity to appear in a Fringe play directed by Sir Ian McKellen. What Andy doesn't realise, though, is that it's a gay production."
Andy then squirms when Sir Ian demands that he snog him on stage and requests a pot of Vaseline from a stage-hand. "It's about being a fish out of water. Andy is not a bloke who goes down the pub and has 10 pints with his mates, but he's not at ease with the luvvies either. He's out of place wherever he is in the world."
What's in it for the A-list stars, though? According to Merchant, "they don't need our credibility. They're doing it because they think they might have a fun couple of days with us. For big stars, it's the equivalent of a trip to Alton Towers."
Gervais and Merchant are in an enviable position. In stark contrast to Andy, they can make whatever show they want. After the mantelpiece-endangering number of awards they have won for both The Office and Extras, they do not have to compromise or suffer executive interference.
Gervais, who has also written and appeared in an episode of The Simpsons, penned two best-selling Flanimals books and mounted two packed-out stand-up tours, stresses that it's crucial that he and Merchant direct their own stuff. "That way, we cut out the middle-man," he says. "We could be offered the best director in the world, but we'd turn him down because only we know what we want."
The pair are also in the happy situation of not having to take gigs just to pay the bills. "If I wanted a quick half a million pounds, I'd do one of the many ads I've turned down over the past couple of years," Gervais says. "I'd never do anything for money. Integrity is a luxury, and now that I've got money it's certainly easier to turn things down. But I can honestly say that I turned them down even when I didn't have any money."
Gervais, who performed his legendary "Flashdance fused with MC Hammer shit" dance in front of an audience of several billion at Live8 last year, continues: "Because success came to me in my thirties, I've seen enough to know that money doesn't make you happy. Poverty is rubbish, but the more you do things just for the money, the less proud of them you are. I want to be able to sleep at night. I'd rather people said: 'Oh, that's the bloke who did that dance,' rather than, 'That's the bloke who advertised beer.'"
The comedian, who hails from Reading, has absolutely no yearning to live in the limelight. "I don't take coke, I don't hang around on the red carpet, I don't come out of Chinawhite with a slapper on my arm, and I don't phone the press to say, 'I've got a great story - my cat's ill!' That sort of behaviour is embarrassing.
"I live with Jane, a cat called Colin and a salamander called Tel. I like to watch Deal or No Deal. I'm in my pyjamas by six. We eat, we open a bottle of wine. We dread it when we have to go out."
Above all, as Extras so compellingly shows, Gervais and Merchant are alive to the very real dangers of the desperate desire for celebrity at all costs. "If I came up with a rubbishy game-show idea," Gervais observes, "they'd make it. But it's like It's a Knockout - you mustn't play your joker unless it's your best event. It's dangerous to think you can do anything. That's when you blow it.
"I'm very careful about what I accept. I've resisted things that are fun because I'm very aware of the amount of goodwill you're dealt. I don't not do panel games because they're beneath me, but because I'm wary of people getting fed up of the sight of me.
"I'd love to do QI or Have I Got News for You. But what's the best that can happen if I appear on one of those shows? I have a great day. What's the worst? People say, 'I'm sick of that fat bloke trying to be funny.'"
After a day in their lively company, Gervais and Merchant continue to banter for Britain. As I head for the exit from Pinewood, behind me the pair are still rapping away. Now they are discussing the boom in celebrity magazines. Merchant muses, "I suppose people want to see pictures of Kate Lawler rather than Jonathan Miller on the beach..."
"Although he has got excellent legs," Gervais interjects.
"Yes," ripostes Merchant, unwilling to be bested. "But I'm not sure a man in his position should wear a thong..."
Extras begins on BBC2 on 14 SeptemberReuse content