He is smaller, slimmer and somehow much tidier than you'd expect. Simon Callow in the flesh, however, is still unmistakably Simon Callow off the telly - brisk of manner, slightly regal of demeanour, fond of sending himself up. In short, an actor par excellence, with the emphasis on the "tor".
When I mention that I loved his story about his granny's Shakespeare, his eyes widen in genuine surprise. "Where on earth did you . . ?" he wants to know. He wrote about it for the Sunday Telegraph last April, I remind him. And as soon as he remembers the source, he's off.
"They were edited by Dr Dibelius of Berlin. Four big volumes: tragedies, comedies, histories and romances," he says. "And they were illustrated with engravings, very romantic, traditional, Victorian engravings. I absolutely adored those books. I pored over them."
So reading Shakespeare posed no problems for a six-year-old? "What happened with me was - when are people supposed to start learning to read? Five? Well, I was a bit behind. I didn't learn to read until I was six, and then it was unstoppable. I read everything I could get my hands on, and these were one of the first things. And, of course, the good thing was, I didn't understand what I was reading about, really, at all. I just read it out loud and wept unstoppably at the emotion generated."
He chuckles drily. He was already, he says, "a sort of full-time performer" at the age of six. "I worked my way through my grandmother's wardrobe. I was always very keen on being somebody else. Character roles, mostly. Every birthday and Christmas my main present would be a costume."
What sort of costumes? The answer, his face arranged into a rueful little moue of distaste, is shot back before the question is even out: "Policemen, I regret to say . . ."
This is the sort of split-second comic timing which made Callow's recent readings of P.G. Wodehouse's Jeeves series for Penguin's audiobooks so delightful (he recently won the best male performer category at the Spoken Word Awards 2001, as well as the gold award for Abridged Classic Fiction, for Thank You, Jeeves). It is also redolent of a certain type of Englishness - irony α l'anglaise, perhaps, a core of mildly spicy self-deprecation overlaid with a languid custard sauce - familiar from several of Callow's best-known roles. Think of the Reverend Beebe in Room with a View, galloping around the garden pond in his well-upholstered birthday suit; think of gay Gareth from Four Weddings and a Funeral.
It comes as no surprise to be told that Callow's instinctive childhood gift for performing was nurtured by frequent teenage trips to that bastion of British theatrical tradition, Laurence Olivier's Old Vic.
"The school I went to was called the London Oratory. It's the school where Tony Blair's children now go - but it's a very different school to the one that it was," he says. "We went to see plays because in those days the Inner London Education Authority, in its enlightened fashion, used to give us tickets. It was incredible what we saw. We saw A Flea in her Ear with a wonderful cast headed by Geraldine McEwan; we saw Olivier in Dance of Death; we saw Much Ado with Maggie Smith. I couldn't believe it. But then there hadn't been anything quite like it in the English theatre.
"There was a tremendous sense of mission about Olivier's National Theatre - a sense that theatre would break through into some new level of communication, that it would be the centre of an informed society - which has gone completely right out of the British theatre. It has disappeared. Gone."
What, even from, say, the experimental edges of the Edinburgh Fringe? "Absolutely. Again, I was very much a part of that in the early days - and there was this great sense that we were going to say the unsayable," Callow continues. "That we were going to risk everything theatrically, that we were a new breed of actors - quite rough, quite dangerous, anarchic, wild. And now it's just, you know. . ."
He spreads his hands. He doesn't want to be disparaging, but . . . And now he is bringing Dickens to Dublin. Which is a tale of at least two cities, since the inspiration for the one-man show that Callow will bring to the Dublin Theatre Festival, The Mystery of Charles Dickens, was Micheβl Mac Liammoir's The Importance of Being Oscar. Callow first saw it when, as a student at Queen's University, Belfast in 1968, he worked briefly as Mac Liammoir's dresser.
"I'd see the quivering mass of nerves and dread, whom I had literally pushed on to the stage, transform into this infinitely intelligent, witty, compelling individual," Callow says.
"Something I've always said to actors when I've directed them, or talked to them, is that the job of the actor is not to make the audience laugh - it's to make the audience witty. Wake people up so that they can make connections for themselves. Mac Liammoir did that. He told the story through a sort of prism, using Wilde's characters and splinters of Wilde himself, as in a mirror.
"And the effect of this wonderful structure that he had created was to evoke Oscar Wilde in such a way that you felt you really had spent an evening, not just with Oscar Wilde, but inside Oscar Wilde's brain."
Callow went on to have a major success with the Wilde show at the Savoy Theatre in London. He had to wait a little longer to get to Dublin."I wrote to Mac Liammoir saying: 'You might not remember me, but I was your dresser in Belfast. Can I have an audition? He gave me an audition, but didn't give me the job. So I've only waited a mere 30 or so years to act in Dublin."
Callow guffaws with laughter. He can honestly say, hand on heart, that it has been his lifelong ambition to work on the Dublin stage.
But why Charles Dickens as the subject of a one-man show? "Dickens is literally part of the fabric of the English-speaking world. Even people who haven't read his books know him from the television," Callow says. "Look at the language, the fact we have the word 'Dickensian' - and he's still on the 10-pound note."
Callow, however, relates, not so much to Dickens the public institution as to Dickens the personal enigma. "Even readers of Dickens don't tend to know much about his life," he says. "Somebody asked me, years ago, if I'd like to play Dickens doing the public readings - and it was when I was doing the background reading for that, that I suddenly engaged with the man. I saw certain things which I was very sympathetic to. I saw a man who was a workaholic, very driven, a man of inordinate energy, obsessed by communicating and somehow not really getting it quite right in certain emotional areas of his life."
He approached Dickens's biographer, Peter Ackroyd, and The Mystery of Charles Dickens was born. It has been an astounding success.
"Fourteen weeks on the road and 18 weeks in London, so that's - erm, what is it? - 32 weeks. Yes, 32 weeks at eight a week, so that's about - um - quite a lot. But I never tired of it. Audiences were wonderfully engaged by the combination of the ongoing chronological story and the constant richness of the characters. I mean, I play 49 characters in it."
Inordinate energy is all in a day's work for the tireless Callow. Since the end of that Dickens run he has completed three films: an adaptation of Dava Sobel's book, Galileo's Daughter; the role of Dickens in a biopic about Hans Christian Andersen; and a film called Thunderpants, in which the main character is a boy who suffers from flatulence. He has just written a screenplay from Christopher Isherwood's novel, Mr Norris Changes Trains, which he hopes to direct - and act in - next year. He is also a regular on the audiobooks front.
Careful study of his chunky resumΘ reveals that he has directed a number of operas, from Gian Carlo Menotti's poignant study of asylum-seekers, The Consul, for Holland Park Opera, to an outing at Scottish Opera for Strauss's fluffy Fledermaus. He has written a jaw-dropping amount of what he succinctly describes as "stuff for newspapers".
Then there are the books, among them Being An Actor, biographies of Orson Welles and Charles Laughton, and the memoir Love Is Where It Falls, . Their quantity - and, more to the point, quality - suggest that he might have been a full-time writer.
"It is what I wanted to do," he says. "I wrote all the way through my adolescence - but I was so bored by what I wrote, because I'd had no life, you know? Then I got into the theatre and suddenly realised that I had my subject. It's almost the thing that I most enjoy doing, but it's not lucrative in any way. Those books are just sheer financial loss on a massive scale. It's like bleeding money out of your system. You could make the same amount of money out of doing a commercial - which is one day's work."
Nevertheless, he is writing a sequel to Being an Actor, which he describes as "an autobiography, but not an intimate one, not confessional". He has already done the confessional thing with Love Is Where It Falls, praised for its searingly intimate portrayal of an unusual triangle: himself, the agent Peggy Ramsay - 40 years older than Callow and besotted by him - and his lover, a young Egyptian manic depressive called Aziz.
Aziz committed suicide and Ramsay died of cancer. Was it bravery or madness to write about such things?
"I wanted to preserve Peggy in some sort of way," he says. "I wanted to, partly, give her to the world, partly just nail her for myself. And it was an extraordinarily painful process.
"It was terrible. It was like living through it all again. The events encompassed by our relationship were profoundly disturbing to me, so to face all that again was a very grim process. But that's why I'm an actor. I need to externalise things, carry them around with me, live with them. In a sense they become more real to me when they're on the page or on the stage."
The Mystery of Charles Dickens by Peter Ackroyd, with Simon Callow, directed by Patrick Garland, opens at the Gaiety Theatre on Monday, October 8th. Dublin Theatre Festival: 01-6772600. Website: www.eircomtheatrefestival.com