Radio Times(Updated)

No, the mulled wine hasn't gone to your head; there really are two Doctors in this year's Doctor Who Christmas special! We head behind the scenes of this eagerly anticipated festive favourite to find out exactly what's going on, and ask whether David Morrissey's taking over the role…

So this is Christmas. We're at Cyber HQ in London 1851 – in reality a set at Cardiff's Upper Boat studios in April 2008. This is Torchwood's Hub cunningly redressed for this year's Doctor Who Christmas special as a sort of huge Cyber-Victorian engine – all cogs, chains, furnaces, pipes and steam. Think steampunk. Or a huge version of the board game Mouse Trap.  

Even before reading the script, I was attracted to this part,” says Morrissey when RADIO TIMES joins him in his trailer over lunch. “DOCTOR WHO is great. They've asked me to do stuff before, but because of other commitments I was unable to. Then this came along: the Christmas special, which has added kudos and an amazing character. Well, the ultimate character, really. But a tragic character, too. Something terrible has happened to him. Over the course of the episode, bits of what happened are revealed...  

Morrissey explains his approach to nailing his Doctor: “There has to be an inner truth for me, something at stake, and you have to play that for real.” So did any former Doctors influence his performance? “When I look at Tom Baker and William Hartnell, there's a truth to their performances; Patrick Troughton as well. They never saw it as a genre show or a children's show.  

“The difficulty for me is green screen [for special effects] – trying to create a relationship with something that isn't there. It's just a man holding a scaffolding pole with a tennis ball on the end. It's a weird process. At least with the Cybermen, their cold, emotionless faces are right there, so you can react to them. Plenty of kids will sleep with the lights on come Christmas night.”  

In Cyber HQ, however, the Cyberleader is in a bit of a pickle. His arm keeps falling off. (Well, part of his arm.) Not so scary now, eh? “He's a decomposing Cyber Controller,” quips Tennant. “Hang on. No, he's a Cyberleader, isn't he? Easy mistake to make.”  

“Call yourself the Doctor?” Morrissey tuts in mock disgust. Would Morrissey consider a return to Doctor Who? “Oh yeah. Definitely. I love it. I've had a great time.” As speculation gathers pace about who'll take over from Tennant, Morrissey is, perhaps unsurprisingly, the bookies' favourite. “If they asked me back,” he says, with a twinkle in his eye, “I'd jump at it. I think it's a great character, and I've loved every minute.”