David Tennant and Russell T Davies David Tennant and Russell T Davies 2009 not only marks the beginning of the end for 9th Doctor David Tennant, but also for the man who introduced Doctor Who to the naughties, Russell T Davies.

But how will their time in the Tardis end? We caught up with the dynamic duo to find out.


What will the tone of the specials be like?
Russell: The Waters of Mars is one of those claustrophobic, submarine-type dramas, with them all trapped in an enclosed space with increasing darkness and intensity.
David: Planet of the Dead was the last hurrah for the 10th Doctor. He was in mortal danger, but he was loving it. Really, from The Waters of Mars and heading into that final story, the sword of Damocles is dangling, and that informs everything that goes on.
Russell: The finale is an epic, almost like a fairytale. But, it's really intimate at the same time. It's got funny little aliens with green spikey faces running around.

How was the dynamic on set with the Doctor's new companions?

David: It's been slightly different in each one. It's been great to get to play these different facets of the character. The Doctor is slightly on the run from himself, and on the run from the inevitable, so he's trying not to get too close to anyone. So it's important that there is a revolving door of confidants for him.

In the next special the closest thing we have to a companion is Lindsey Duncan, who is an older woman, which is not something the show has done before. She probably thinks she's more in charge than the Doctor is - in many ways, she is actually, so that's a different dynamic.

Doctor Who: Christmas Special 2009David on set with Bernard CribbinsAnd then, although Catherine Tate is back and Donna is a big part of the final story, the companion really is Bernard Cribbins, and that is the first time the Doctor has had an 80-year-old man as his sidekick. The Doctor is a lot older than Wilf, and yet the two of them sit down and discuss life in a way that we've never seen before.

After Planet of the Dead, will the remaining episodes all be ramping into the next regeneration?

Russell: Yes. I think this Doctor likes being this Doctor. He's raging against the dying of the light. And that's the beat that we play. That's the story. He knows that the sands of time are running out. He's been told. The bell is tolling for him, and he doesn't want to go quietly. That's how we play that.

David, why leave now, when the show is so popular?

David: Sometimes, you have to take a deep breath and make a difficult decision. I like the fact that I stand a chance of leaving an audience and myself wanting more, rather than people asking when I'm leaving. I never had a definite stepping-off point, but when Russell and Julie were moving on, it seemed like the obvious time. It seemed like a natural end for all of us, really.

Knowing that this is basically the end for you, is it bittersweet?
David: It's very exciting, but it's also very sad. It feels like we're coming to the end of something very special. I don't quite know how it feels. I don't think any of us really do because we're still clinging on until the shows go out.
Russell: We're happy with a job well done.

Since this is sci-fi and we have seen previous Doctor's, would you ever consider a comeback?
David: I'll wait for the correct opportunity, but I've got the costume hanging up in my wardrobe. As long as I can keep my waistline and still fit into the trousers, I'll never say never.

David, what are you doing next?
David: Long term, I don't really know. In the immediate future, I've just done a television version of Hamlet, which is broadcasting soon. And, I'm doing a film called St. Trinian's 2: The Legend of Fritton's Gold, at the moment. But I don't know, after that.

Doctor Who: The Waters Of Mars comes to BBC1 in November, but check out our on set pics for a taste of what's in store.

Read our Doctor Who Interview: Part 1 in which the pair reminisce about working together over the past four years.

Find out when Doctor Who is on TV.