In the very best tradition of the very cheesiest of pantomimes, I don't actually see Christopher Biggins when I first arrive at the south London studio at which he is busy rehearsing Aladdin. The reason for this? He is, in a very real sense, behind me. But I certainly hear him, his big booming voice in full song to the accompaniment of a piano and, somewhere in the background, a far more dulcet Patsy Kensit, who tra la las all the way to the chorus. At the stroke of one, he breaks for lunch, welcomes me like a long lost friend, and leads me to the adjacent cafe where he treats me to a mozzarella panini. The cafe is filled with other actors also in rehearsal - not just unspectacular Hollyoakers, but proper thesps: Simon Callow, his co-star in Aladdin, and, three tables away, Richard Wilson, soon to be seen in Cinderella. This pleases Biggins enormously, and here's why.
"Once upon a time, actors of a certain calibre used to pooh-pooh the idea of panto, considering it beneath them," he says, "but Ian McKellen has changed all that." (The great man last year appeared as Widow Twankey at the Old Vic, under the direction of Kevin Spacey - and is doing so again this Yuletide.) "And now, I'm delighted to say, other actors of a similar clout, like dear Mr Callow over there, have followed suit.
"And that's absolutely essential in order to keep it alive," he continues. "For many people, panto will be their very first trip to the theatre. If they've enjoyed themselves, then their interest in theatre could well last a lifetime. I really believe this, you know. I most sincerely do."
His large blue eyes bulge, and his cheeks, now filled with panini, do likewise.
Christopher Biggins is, of course, a pantomime legend, an appropriately camp-as-Christmas D-list celebrity who has now been popping up in grotesque slap for 29 years. Recently, he has spread his wings into directing them as well, and will this year be presiding over Aladdin at the Richmond Theatre in west London, freshly updated for the 21st century, with Callow as Abanzar and Kensit as the Genie. Biggins himself plays Widow Twankey: "And I do it awfully well!"
Panto first came calling for him back in 1976, when he was but a slip of a man.
"And I was grossly insulted," he chortles good-naturedly. "Pantomime dames were always played by hideous old men, so why on earth did they ask me? I was 28!"
He turned it down flat. Then, after they'd upped the money, he had a change of heart. But he is insistent that it wasn't just the cash that convinced him. It was the role itself, Mother Goose: "The Hamlet of dames, a genuine acting challenge."
Instantly, he'd found his metier.
"Because of my size, I tend to look funny in women's clothes ... And I've added my own twist to the part. Traditionally, pantomime dames are rather nasty, but I'm entirely lovable." His chortle becomes a guffaw. "I'm like your favourite aunt and mother-in-law rolled into one!"
But while he may laugh (and chortle and guffaw and, in time, titter and cackle), panto is something he takes very seriously indeed. He recently formed a kind of watchdog collective, which effectively conspires to keep these annual productions free from the clutches of third-rate comedians and, worst of all, celebs. "We've had people like Frank Bruno doing panto. Ridiculous! Don't get me wrong, he is a very nice man and I love him dearly, but he's no actor. " They also had that cricketer recently - whatshisname?" Ian Botham? "Ian Botham! Can you imagine?"
And don't even get him started on the Hamiltons.
"[Neil and Christine] marched up to me at a party recently," he says, "and Christine told me off for being so nasty about them in the press [after they'd appeared in a seasonal production of Jack and The Beanstalk]. I just said to her, Sorry darling, but you simply shouldn't be doing it. Just as I shouldn't get into politics ... Anyway, my point was that panto should be reserved for proper actors only, and my productions always are. I defy anybody to come to one of mine and not be absolutely riveted by it."
A fist goes up in the air, and comes down hard on the table.
Momentarily, the cafe falls quiet. He beams with deep satisfaction.
Quite possibly unique within the industry, Christopher Biggins possesses a singular kind of fame. He is instantly recognisable, but it isn't always clear what for, exactly. He has been a household name for close on 30 years now, a self-confessed "personality" (his inverted commas), who is photographed at endless red-carpet events, and usually with a glass of Bolly in hand. But talk to him, and he is quick to remind you of his work: "Theatre, TV... voiceovers, I've done them all!"
He speaks almost exclusively in italics and exclamation marks, and peppers his conversation with sentences that begin, "If I won the lottery..." or, "If I were rich...", despite appearing to live a life of almost constant luxury. Rarely is there a society party to which he has not been invited.
"Ah, but that's because I'm the luckiest person in the world, Nick. Truly! I have so many kind and generous friends who ask me to all these wonderful events, and so in many ways, I am a millionaire without actually being one."
He has recently spent three months travelling the globe with his partner of five years, a BA pilot whose staff discount enabled them to do so for just £350: "And that was Club Class!" He spent last weekend at a party in Moscow, where he hobnobbed with the filthy rich, and Joan Collins, one of his closest chums, once introduced him to Frank Sinatra and George Burns on the same night.
"It amazes me just how far I've come in my life," he coos, eyes aflutter.
Born in Oldham in 1948, his family soon relocated to Salisbury where he attended private school and underwent, at the insistence of a "snobby" aunt, elocution lessons. These led to theatre groups, and by the time he left school, he was working in the local rep. Had he employed a better agent, he might have become a regular in the Carry On series, but instead had to make do with a succession of sitcoms (Porridge and, for children, Rentaghost) and game shows (On Safari, Surprise, Surprise!, the latter occasionally necessitating him to dress up in a gorilla suit).
Despite Surprise, Surprise! "bringing me even more greatness," he abruptly quit after one series, desperate to exercise his real talent. This, after all, was someone who once played Nero in the BBC's I, Claudius. But by now Biggins was typecast as, he says, "this bubbly personality", which effectively killed his chances of ever being taken seriously as an actor (with emphasis on the second syllable). I ask him if he secretly wishes he had Derek Jacobi's career, and whether he craves respect from an industry that seemingly refuses to bestow it.
"No, not a bit of it. I'm perfectly happy being me, thank you, and I happen to know that I am afforded enormous respect from everybody I know. And anyway, I'm having something of a second wind now. I've reached the age  where all kinds of roles are opening up to me."
He has recently completed a stint scaring children in Chitty Chitty Bang Bang in London's West End, and has just filmed an American mini series called Revelations, in which he played a cardinal. Ant & Dec, meanwhile ("those darling, darling boys") are positively begging him to do I'm A Celebrity.... But right now, his focus is purely on panto.
"If I'm entirely honest with you, Nick, and I hope I can be, I look forward to the day I wake up one Christmas morning in Mauritius to a champagne breakfast, knowing I'll never have to do another pantomime again. Out of everything I do in my career, this is by far the hardest. Twelve shows a week for six weeks can really be really gruelling."
Which is why, presumably, he "rests" for the remainder of the year?
"Just because I'm not on television doesn't mean I'm not working," he says, throwing me a theatrical scowl. "There are always projects on the go. I've lost count of the amount of taxi drivers who tell me they thought I was dead. Well, I'm not dead. I'm very much alive, and I intend to prove it!"
Chortle, titter, cackle. Repeat to fade.
'Aladdin' is at the Richmond Theatre, London (08700 606 651) from Thursday