Caldwell skilfully melts the heart of Sam Ryan (Amanda Burton), the ice- queen pathologist, with his combination of cleverness ("Facts are always subject to interpretation, aren't they? That social science foundation course wasn't entirely wasted on me") and charm ("I'm not a dangerous man, believe me").
Dee found himself enticed by the ambiguity of Caldwell. "I like the contradictions in the character," he says. "When he comes out of prison, he's desperate to go straight, but he can't tear himself away from the lifestyle and the mindset he was in before. Circumstances around him prove greater than his resolve to change. That's an interesting dilemma to play out."
But just why are performers such as Dee, Robbie Coltrane, Billy Connolly and Alan Davies increasingly exchanging smiles for scowls? According to Dee, "It shouldn't be a surprise. In fact it would be a surprise if comedians weren't turning to acting. Comedians are involved in timing and delivery. We're also in the business of telling stories and creating pictures for an audience. That's a useful technique. We have the ability to look at a script and see how to bring it to life."
Although he is currently starring alongside Jonathan Ross and Julian Clary in BBC1's not universally acclaimed new comedy panel game, It's Only TV... But I Like It, Dee has been showing his other sides. He's had two runs in the hit West End play Art, played an irksome PE teacher in the pilot of ITV sitcom The Grimleys, and took the role of a sinister cult leader opposite Pauline Collins in BBC1's Ambassador.
Acting provides Dee with a sort of career life-insurance policy. "With stand-up I got to the point where I thought, `Yes, I can come up with a new show every two years, but is that what I want to do for the rest of my life?' So I went into Art and took it very seriously for a year because I wanted to be able to look other actors in the eye. I didn't want to be seen as a celeb allowing his personality to be grafted on to various dramas just for the sake of it. I consider acting a great challenge and discipline."
Particularly in something as serious as Silent Witness, not noted for its high laughter quotient. Dee says he jumped at the chance to play Caldwell: "I knew the calibre of the series and, to be honest, I would have done it even if I was playing Coco the clown."
But, rather than a circus joker, Caldwell is what actors most relish playing: an insinuating baddie. "When actors talk about being attracted to certain roles, they always neglect to say that it was the only thing they were offered," Dee laughs. "But there is a fun side to baddies. They are dramatically more complex than inherently good people. I also liked the challenge of presenting the audience with a baddie you care about. If people don't like baddies, it doesn't matter when they meet a sticky end. Drama shouldn't provide you with ready-made emotions. It's a cop- out to be told what to think all the time."
Dee reveals that "there is quite a serious amount of interest in me as an actor. There is a BBC drama which has got my name on it."
Perhaps that will stop people seeing him as just a simple gagsmith: "I like to surprise an audience and deliver something they were not expecting. That's crucial to a performer. If that's not your motivation, you're just providing people with what they expect. That's a short cut to going very stale very quickly.
"I say good luck to people who can do that, but I can't," Dee concludes. "I would wake up in the night thinking, `Why am I doing this?' You question yourself if you allow yourself to become a tart."
A two-part `Silent Witness' is on BBC1 on Tuesday and Wednesday at 9.30pm
James RamptonReuse content