JIM Carrey is standing in the shadows with his back to the door, dressed in a long black coat. He turns and emerges out of the darkness, smiling widely, hand stretched out for a very firm shake.
It takes you aback for a minute to see a face so familiar, so famous and so much larger than life, in the normal surroundings of a London hotel room.
"One of the fantastic things is when I have a 10-year-old or an eight-year-old come up to me and their parents say, 'Do you know who that is? That's The Grinch'," he says excitedly.
"And they go, 'The Grinch? It doesn't look like The Grinch!'"
Suddenly his face alters so dramatically it almost seems like it is changing shape.
Without a smidgen of make-up, and without any warning, he morphs into the famous Doctor Seuss character.
"I must find a way to stop Christmas from coming!" he booms in the Grinch's tones. "And they just freak out!" he adds with a laugh.
"So now I get 10-year-olds and also the 40-year-olds, who come up to me and say, 'I grew up with you, man!'
Be it with The Mask, Ace Ventura: Pet Detective, Dumb And Dumber, Liar Liar, or Bruce Almighty, it's hard to find someone who does not have a fond memory of a Jim Carrey film.
He has been a box office draw for more than 25 years, not just for his zany brand of comedy, but also for serious roles in The Truman Show, Man On The Moon and Eternal Sunshine Of The Spotless Mind.
"And somehow I'm still here," he jokes. "And I'm trying with all my strength to defy the lethargy that is knocking on the door, saying, 'Just give up, you've done enough! Haven't you proven yourself?' No! No, I haven't!"
His latest character is the eccentric villain Dr Ivo Robotnik in the live action Sonic The Hedgehog movie, based on the hit Sega video game. Carrey appears heavily mustachioed, with dark brows, as the evil but dance-loving genius trying to track down the speedy blue hedgehog on which to carry out experiments.
"I'm a bit of a dancer in life," he says. "I don't just cook, I dance the kitchen. It becomes a routine and maybe it's the early Fred Astaire films and stuff like that, that just make me want to kind of float through life and occupy the space.
"This character and this film is just right for this sort of situation, where it just allows me to be completely free. It's like somebody took the gate off the comedy corral and let the mustang run, it's really fun."
Carrey is now 58 but he still embraces the energetic slapstick.
"When they conceive of a character, it's not really fleshed out on the page but there is enough of it there to understand it. When I get into the psychology of the thing, you might not think I go very deep, sometimes it looks like lightning comes from the clouds, but it actually comes from the earth.
"It comes from an understanding of the emptiness inside this guy, the combination of pure genius and total worthlessness in his own mind, it is a wonderful explosion of comedy.
"Then there is also the AI aspect of cars that are driving themselves and stuff, and soon Robotnik, if he has his way, will take the steering wheel and drive you to hell, make you take a hard left on the freeway."
That sounds something like an existential crisis?
"We are all having it, aren't we? This is the character that takes the edge of it a little bit."
Carrey is a grandfather now – his daughter Jane has an eight-year-old son, Jackson – and he thinks about that when he is making his films.
"Oh yeah, absolutely," he affirms. "My daughter and my grandson. And every kid, honestly, every kid."
He's still gratified when someone dresses up as one of his characters for Halloween, and his bucket list is looking pretty empty.
"I don't have a tremendous amount that hasn't already happened," he says. "I can look at my life and literally from the neck down I'm black and blue from pinch-me moments. It's just incredible, this life I'm having, so I feel so gratified.
"I think I will always be joyful about being creative. At this moment in my life it just seems to be expanding and flowing over the edges in every direction."
He will release a book soon, a novel called Jim Carrey: Memoirs And Misinformation, which he describes as "an avant garde memoir treatment of persona".
I must look confused so he expands.
"It's not just about me, it's about you. My dream for that book is that it's not only something you read but it is something that reads you. So it's as close an understanding of what goes on inside me as you will ever get."
For now, life is pretty good for Carrey.
"I'm just happy when I'm able to play something or do something that is a new swing for me, and at the same time the possibility of creating another character that kids dress up as on Halloween...
"One of the major – I will call it a bucket list – things I had when I was younger, when I was dreaming up everything I wanted in the world, was that I would wish for the type of work that reintroduces itself to people, generation after generation.
"And I got that in spades. I just really lucked out and I feel super gratified about it.
:: Sonic The Hedgehog is in cinemas from today.
