"I suddenly think the job of acting is a difficult one," says Rowan Atkinson. "It's not as flip, irrelevant and shallow a calling as I thought it was in the Eighties."
Atkinson, who is preparing to make his "straight play" debut as the lead in Richard Eyre's West End revival of Quartermaine's Terms by Simon Gray, is globally famous for playing an absent-minded, middle-aged buffoon who says next to nothing. He's also notorious for giving away as little of himself as possible: an interviewer once reported he was so reluctant to disclose anything about his family he refused to acknowledge the existence of his children. (For the record, he has two, Lily and Benjamin, with his wife, Sunetra.) So, ahead of a rare interview with him in a London members' club, I'm unsure what to expect.
My trepidation is increased by the fact that I grew up when Atkinson was lending his malleable features and gift for physical humour to two of the defining television comedies of the Eighties: Not the Nine O'Clock News and Blackadder. He ranks as one of the true greats of British comedy, his status cemented by the enduring power of the material that propelled him to prominence in the late Seventies and early Eighties. In 1981, at the age of 26, he became the youngest performer to have his own production in the West End, a self-titled revue show for which he won an Olivier award.
In the three decades since, his two studies in the art of bumbling masculinity - Mr Bean and Johnny English, the Bond-spoof inspired by his lucrative ads for Barclaycard - have made him fabulously wealthy (with an estimated fortune of 71 million pounds) and recognised around the world. His triumphant appearance this summer in the Olympics Opening Ceremony, where he clowned around while continually hitting the same key of a synthesizer during the London Symphony Orchestra's mock-magisterial rendition of the theme-tune from Chariots of Fire, rubber-stamped his status as a national treasure.
Is he grand, awkward or aloof as a consequence of all this success? Answer: none of the above. In person Atkinson is only too happy to chat. Dressed in jacket, shirt and jeans and with his glasses removed for the conversation, he could hardly look more unassuming; only his inimitable way of knitting his eyebrows or rolling his eyes slowly from side to side in contemplation gives one flashes of the facets that he so often exaggerates in performance.
This coup for theatreland came after an approach from the producer Michael Codron, who mounted the premiere of Gray's play in 1981, in a production starring Edward Fox and directed by Harold Pinter. For most of his career Atkinson, 57, has shunned theatre after a stint co-starring in an evening of Chekhov shorts, The Sneeze, in 1988 which left him singularly underwhelmed.
"It was a success, but I made the mistake of signing up for six months and I lived to rue the day," he says. "That more than anything was what put me off theatre. I couldn't understand what the point was of doing the same thing every night. I found it was a case not so much of reinventing the wheel as presenting the wheel again and again." He gives a little snuffle of laughter.
His first stage role since then, playing Fagin in Oliver! at the Theatre Royal Drury Lane in 2009 - a demanding nine months, broken only by three weeks off to recover from a hernia - "reignited" his faith in theatre. "I had the strange feeling in the middle of the run, for the very first time, that I was in a worthy profession," he says. "Maybe it's because I was a cog in a big machine but there was this wonderful sense of shared responsibility.
"Here was a group of professionals - actors, musicians and stage technicians - coming together to put on a show. I thought 'This is a good thing', whereas in 1988 I was just thinking 'This will be a bit of fun'.
The role of the other-worldly and rather clueless St John Quartermaine - one of a bevy of sad-sack teachers stuck in an English language school in Sixties Cambridge - is a typically canny choice for a man who has seldom put a foot wrong in his career; the weakest link on his CV is probably Ben Elton's mid-Nineties police-station sitcom The Thin Blue Line, but even that had its amusements.
There may be points of connection between Quartermaine and the hapless Bean but this is still a significant departure. For one thing, the room for physical manoeuvre is limited - as Atkinson notes, St John spends "most of the evening in an armchair doing bugger all". It may also be that this will be the first time that Atkinson has made us cry.
He saw the original production in 1981, adored it and admires the play - Gray's own favourite - hugely. "It's well known that tragedy and comedy are close bedfellows," he says. "It's rare, though, that you see them placed in such intimacy. Like most tragic figures, Quatermaine is unaware of his own tragedy.
"What I love about him is his optimism. You don't tend to feel much sympathy for pessimistic people but those who retain their optimism despite the sadness of their lives are interesting, engaging and sympathetic."
He admits to feeling a certain kinship with the character. "I've played quite a few of these sad, isolated bachelor figures - Bean is the most obvious," he says. "And I think I do identify with them or aspects of them. I hope I haven't led as tragic a life but I'm well aware that I'm someone who is quite content to sit in a room and do nothing for 10 minutes except stare at the wallpaper and think. I'm quite capable of being alone in my thoughts." He pauses, smiles. "And I'm perfectly happy with that mode."
Brought up with two older brothers on a 400-acre farm near Newcastle, Atkinson showed little relish for the performing arts in early youth, had a stammer from childhood (traces of which are still apparent) and was set on a nerdish trajectory, studying electrical engineering first at Newcastle then Oxford University, where the siren-call of student comedy lured him on to the stage. At Oxford, he became friends with future screenwriter Richard Curtis, a meeting he describes as one of the great pieces of luck in his life.
His first act came about quite simply after he pulled some faces in the mirror, found them funny - "and merely on the basis of that I concocted a feeble narrative about a man trying to give away a piece of paper to a member of the audience - it was a sketch with literally no content". What surprises him looking back is the confidence he swiftly assumed in performance, the extrovert flip side to his instinctive introversion.
His much reprised breakthrough sketch, playing a teacher reading out a register at the Amnesty Secret Policeman's Ball in 1979, revealed what he describes as his "lack of a need to please the audience in an immediate or obvious way".
Performing at the Olympic Stadium this summer held little terror for him, he says. "I don't think I'd ever performed a sketch in a vast stadium but I think it's far more terrifying to stand up in a wedding reception in front of 40 people in your local church hall." Confronting a stadium audience, he explains, "You can't see the whites of their eyes. It's just an amorphous mass of noise and, of course, you can't see the alleged billions watching at home either, so the degree to which you are intimidated is quite low. I focused on trying to get the joke right."
He was pleasantly taken aback by just how much acclaim his cheeky, subversive appearance - the essence of everything Danny Boyle was trying to do with the event - garnered, and has a typically modest explanation. "I don't think I've ever done anything which has attracted such a positive response - with virtually everything I've ever done, there have been lots of snipers and dislikers.
"I think we benefited hugely from the element of surprise. In the modern media age, we are rarely surprised by what we see. Whether it's on television or film or in the theatre, everything is so advertised, so trailed, that most entertainment is merely what you thought it was going to be like. The idea of sitting down in front of something about which you know absolutely nothing is very rare and that's what we had."
His wordless antics were hailed by some, understandably enough, as being in character as Mr Bean. They weren't and, also for the record, he thinks his bug-eyed creation may well be nearing the end of the line. "The stuff that has been most commercially successful for me - basically quite physical, quite childish - I increasingly feel I'm going to do a lot less of. Apart from the fact that your physical ability starts to decline, I also think someone in their fifties being childlike becomes a little sad. You've got to be careful."
Not that he regrets the character - even though it has typecast him to a degree: "He's a rod for my own back because people realise that whatever you do, in film especially, you're going to bring the baggage with you, the perception that you're the bloke who plays Bean - so inevitably it's sometimes difficult for people to see you in other roles." Bean, he says, "is widely disliked among the chattering classes but that doesn't worry me. I'm aware of the rewards of doing it, and they're not just financial."
So what can we expect in the future from Atkinson? More interventions in the ongoing public debate about the right to freedom of expression; he's recently helped launch a new campaign to repeal clause five of the Public Order Act, and its increasingly abused inclusion of "insulting behaviour" as a potentially criminal activity. "I do feel strongly that I've enjoyed tremendous freedom in my life," he says, "and I would like that to continue into future generations."
There will be more collecting and driving of fast and expensive cars - the McLaren F1 that he crashed last autumn, after skidding on a wet road, is due back from the garage any week now. There will be more pottering about too: "I like to juggle with one ball at a time," he says. "Then I put the ball down and do nothing for extended periods of time." There are hints he may have a go at bringing a new comedy sketch show to the stage, but in the main he hopes there will be more theatre.
"I'd be amazed if this was a one-off," he says. "To an extent it depends how it goes but I do like theatre, I feel comfortable in the medium. In the end, there's nothing like it, as long as I can find roles I feel I could play."
Serious without being solemn, quietly self-confident without being smug, he leans forward. "I don't regard it as a plaything. I want to believe that I could play parts as well as anybody else. If you think, well actually Michael Gambon would be much better than you, you shouldn't be doing it." He frowns affably. "I don't regard this as something I'm simply having a stab at."
Quartermaine's Terms runs at Wyndham's Theatre from January 23 to April 13. Tickets: 0844 482 5120. It previews on tour at the Theatre Royal Brighton (January 8-12) and the Theatre Royal Bath (January 14-19)