Benedict Cumberbatch stalks into a room full of nervous reporters, wearing a plaid shirt under a padded leather jacket, his crowning glory shorn of trademark Sherlock curls and restyled into a close-cropped block with its edges teased by wax into tiny, furry undulations.
He brings to the interview a styrofoam cup of hot coffee murmuring a faint, fresh mist on the black-rimmed glasses perched on his face. The glasses come off immediately as the actor takes a seat, facing his questioners head-on with a clear-eyed stare.
Cumberbatch is here to answer questions about his latest movie pursuit as cryptographer Alan Turing in director Morten Tyldum's The Imitation Game. Except, of course - that he has already pre-empted them all with a stream of ready, authoritative oration.
"He was wonderful, he was entertaining... I spoke to his niece after I read the script and was researching the project. She said he never made us feel we were talked down to. He used to crack jokes, he used to be able to play chess with his back turned to the board," the 38-year-old actor recalls.
"He's an extraordinary human being, not such an easily boxed, outsider autistic genius. Yes, the film is about celebrating people who are different - but we define people as different at our own cost. What delineates different behaviour or marks somebody as being remarkable can also be examined under a light that also relates them to who we all are as human beings."
So this is the actor who dashed a few million female hopes two months ago when his parents - both also professional actors - broke news of his engagement to theatre director Sophie Hunter in the pages of London's The Times newspaper.
Coming across almost as arrogant and intelligent as his best-known TV persona of Sherlock Holmes, Cumberbatch charms through unrelenting, beautifully articulated talk.
At the same time, there is a twinkle in his eye which recalls the playful side of a personality that the Internet has turned into memes: through endless re-tweets of a famous photo-bomb at last year's Academy Awards; clips showing his self-conscious mirth at his inability to pronounce "penguin" on a TV chat show.
And still the actor continues: "His character was formed from his circumstances. I don't think he was born with Asperger's. He was born into foster care, his family was away in India on a diplomatic career, he came back when he was four, he had a stammer.
"He went to school where he was to make friends - you can't do that very easily if you had a stammer. All these things fell in... there are no visual or audio recordings of him, most of it is hearsay. At the end, I just sometimes went from the outside in, sometimes from the inside out - I put together the character just bit by bit really - it's different every day."