Sherlock has become an unlikely style icon. Was that a surprise?
We all put a lot of thought into his outfits, so I guess when you get massive exposure on a popular TV drama the look of something can catch on. The gloves and scarf were my idea, and the coat was [costume designer] Ray Holman’s discovery. There's just a clean, linear, functional beauty about Sherlock. There’s nothing showy or flamboyant about him. And I get to wear very well-cut, good-looking suits, although there’s so little waist that sometimes I can’t breathe or digest properly. The sad thing is that I had a coat very similar to Sherlock's before I got the role - it was a present from someone - but I can't wear it out in public now, which is sad.
There's more teamwork between Watson and Holmes this year...
It's true, there is a bit more of a united front. But that’s mostly out of necessity, because they're being thrown the biggest challenges they've had so far. The big arc for Sherlock is that he’s gaining humanity. Or rather it’s being brought out of him. He's on the side of the angels, but his methods can be pretty devilish. Standing on a dying man's neck, saying, "Give me his name!" is quite a tough thing to do, for example, but he's dealing with a world of extremes: corpses, death and suffering.
What scene are you about to shoot?
There's a huge, fuck-off deduction I've got to do today! I’m basically cracking a code that is all to do with Irene Adler. What information she possesses and why people are after her. It’s this constantly slipping, sliding, changing landscape of trust and counter-trust and counter movements. And, at the same time, it’s a massive flirtation - it's a dance between the two of them.
Do you dread doing those scenes?
With deductions, I start learning my lines two or three days before, at the very least, because they're always a very painful birth, as anyone who’s been on set with me will testify. The trick, I've found, is to deliver a sentence while you're already thinking about the next one. The speed of it has to come from thinking, "What's next? What's next? What's next?" You just have to work very, very hard at it, and on the day try to find pockets of time to completely shut off and be quite kind of meditative about it.
Have you ever nailed one in the first take?
Never in the first take, but I have done it in one take. There are some long continuous shots in this sequence, so we'll see...
Are you excited about taking on The Hound Of The Baskervilles?
Yeah, very. We're doing interesting things with it. It’s Doyle's most famous story and it’s one of the ones that features Holmes less. In our version there is a lot of Watson on his own in the field, but we're making Holmes much more a part of it. It's much more of a team effort. It was great to shoot stuff outside, out in Dartmoor.
After this, you're doing Parade's End and then you've got a dual role in The Hobbit…
I’ll be doing bits on The Hobbit in 2012. I’m playing Smaug through motion-capture and voicing the Necromancer, which is a character in the Five Legions War or something which I’m meant to understand. (Laughs) He’s not actually in the original Hobbit. It’s something he’s taken from Lord Of The Rings that he wants to put in there.
Those are two cuddly characters…
Yeah! I'm going to have to keep my smarts about me when it comes to emotionalising a demon and a dragon...
Sherlock: Series 2 is airing on BBC1 on Sunday nights. For Empire’s exclusive on-set report, pick up the issue on sale now.