I've known a while, actually, because we've known for a couple of months. It's by mutual consent - I think really those stories just come to a point where it reaches its conclusion, and the very essence of the show is that it constantly re-invents itself.

(on whether he'd go at the same time) I'm very happy to stay, I love it, I love making the show, but I'll miss Karen because she's a good mate, one of my best mates. She's a cracker - mad as a box of cats - but she's a firecracker, she really is.

David (Yates) was talking a little out of turn, there; a very, very brilliant director but no the film as described by him, of course we're not going to do that - a film that contradicts the television series, it would be a heathen thing to do ... I would be 'beheaded' to do such a thing!

It would be wonderful to do a Doctor Who film, but when and if we did - and hopefully we will be doing it - it will be very much an offshoot of the television series and we'll be part of it, and it will star the television Doctor, of course - anything else would be heresy!

Tennant, who has proved fans' most popular Doctor during the programme’s modern era, is set to make a "cameo appearance" in the new movie with recent Harry Potter director David Yates at the helm.

"It's felt it would be very fitting to have David involved after everything he’s done for the show," said an insider.

Introduction by Steven Moffat

The Doctor at Christmas - it always just feels so right. When I was a kid, Santa and the Doctor somehow lived in the same place in my head - two generous madmen that I loved so much. So now that the Doctor is a regular feature of Christmas the world is just that bit more right.

This time we're in England in the 1940s, and recently widowed Madge Arwell hasn't told her children, Lily and Cyril, that their father has died flying his bomber home over the channel, because she doesn't want Christmas to become the day that broke their hearts.

But when they're evacuated to a draughty old house in Dorset for the holidays, and meet a mysterious young caretaker in a bow tie, events take an unexpected turn. What could be inside that big blue parcel under the tree?

Soon the Arwells find themselves in a battle for survival in a magical new land. As ever, at this time of year, the Doctor is trying to make things right, and as always it doesn't go according to plan. But maybe he's reckoned without the power of a determined mother.

This Christmas, it might just be the lonely Time Lord who's shown the way home.

Interview with Matt Smith

The Doctor, The Widow and The Wardrobe is Matt Smith’s second Christmas outing as the Doctor and this time he doesn’t have his trusted companions, ‘The Ponds’, by his side. However, it hasn’t stopped him relishing in another Christmassy adventure and here he reveals what Doctor Who has in store for festive viewers.

Doctor Who and Christmas go hand in hand don’t they? laughs Matt Smith as he sits down to discuss the special episode of Who, penned by Steven Moffat. It’s a brilliant and touching story about a family who have experienced a tragic event and in many ways they’ve had Christmas stolen from them.

Smith reveals that Madge Arwell and her two young children, Lily and Cyril, have been evacuated during the Blitz to a ramshackled old house in the country where the Doctor has taken up residence as caretaker. The Doctor, in a very ‘Doctory’ way, tries to bring Christmas spirit and cheer back into their lives, explains Smith. “He has ‘Doctorified’ the house so to speak and there’s a magical present under the Christmas tree which is a portal to another world. Cyril enters it and discovers an enchanting landscape that encapsulates the beauty, danger and madness that is Doctor Who at Christmas.

So will viewers be cowering behind their turkey and stuffing sandwiches on Christmas Day? Well there are two scary characters that live in a huge tower and move in a very strange and menacing way, confides Smith with a conspiratorial grin. I also really enjoyed making this episode because the characters unfold in a subtle way and you never quite know what’s waiting around the corner. I also loved working with the guest cast who all seemed to have a whale of a time.

The Doctor has had many festive adventures over the years but what are Smith’s favourite Christmas memories? The best present I’ve ever had was a snooker table when I was a kid, he reveals, although my SEGA Mega Drive came close! I also used to love getting pyjamas and wearing them all day. Plus my granddad absolutely hates dressing gowns so it’s become a family tradition for us to buy him one every year and it always makes me laugh.

And Matt Smith’s recipe for the perfect Christmas?

Family; everyone happy, healthy and together with lots of food, presents and good TV. Oh and football on Boxing Day! I’m really hoping for a white Christmas but if I couldn’t have a traditional Christmas I’d spend it somewhere really warm like South America or Australia and have a barbecue on the beach.

Interview with Claire Skinner

Who do you play in the Christmas Special?
I play a character called Madge Arwell who, first and foremost, is a mother. It just informs everything about her character. What I found attractive about the role is that she’s warm and a thoroughly decent woman, as well as being quite straight down the line. In the episode she gets tested and challenged and it’s interesting to see how she handles different things and adapts to various situations for the sake of her children.

What was it like working with Matt Smith?
Lovely! A really nice experience. He’s thoroughly charming, good fun and has loads of energy.

What about the other guest stars?
I’ve worked with Alexander Armstrong before, so it was great to see him again. We’ve actually been fishing together! Bill Bailey is just completely brilliant; a really nice, natural and funny bloke. And the children as well. Maurice and Holly were just delightful, completely lovely.

Are you a fan of Doctor Who?
Yes for several reasons actually. My son watches it, my husband has directed it before and my father in-law was in an episode. It’s a nice connection to have.

How did it feel being cast in such an iconic show?
I was very excited to be in it, both because it’s Doctor Who and also a great script. When I got the call I was like “Yay, at last I’m going to be in Doctor Who.”

How did you find filming on location?
We shot some scenes outside in a public space and it was an unusual experience acting in front of huge crowds of people who had come to watch. I had to drive a car down the road, which took about 500 takes, and they applauded my driving each time. It was lovely, but I hadn’t been quite ready for that.

What do you think is the scariest Doctor Who monster of all time?
It’s not exactly a monster, but the creepy people in the gas masks in series one were pretty scary. They definitely freaked both my children out at the time.

What will you be doing on Christmas day?
I will be with my family and my husband’s family; a traditional Christmas. We’ll of course be watching Doctor Who.

What other Christmas TV do you like?
I like traditional comedy; I’m such a fan of Morecambe and Wise. We’ve got the box set, so we always get that out at Christmas.

Interview with Alexander Armstrong

What can you reveal about your character?
I play Reg Arwell, who is a bomber pilot in the Second World War. We witness him flying over the channel and all the navigation equipment completely stops working. It doesn’t look good for him! His wife Madge then receives a slip of paper saying that a ‘Reg’ is missing and presumed dead. Their two children hope that their Daddy is going to be back for Christmas and that’s when the Doctor gets involved to return a favour to Madge as she helps him out at the very beginning of the episode.

Did you enjoy working with your co-stars?
Amazing. Lovely to work with Claire Skinner again, I did a drama with her called Life Begins a couple of years ago. But the real treat was working with Matt, who’s just a tremendously fine fellow and an excellent person to hang out on set with. As you can imagine, there’s an awful lot of time between takes and I can think of few nicer people to spend time with than Matt.

Doctor Who will soon be celebrating its 50th anniversary. Are you a fan?
It’s something I’ve always wanted to be in and there really isn’t another show like Doctor Who. The heritage of it is amazing and when the BBC got it going again it suddenly took on a whole new life. It has all the charm and ingenuity of the first incarnation but it also has Russell and now Steven’s really current TV brains behind it, people who are so literate in really good television that gets you thinking. With Christopher, David and now Matt, this Doctor Who has kind of gone nuts. I mean my Doctor Who when I was young was Tom Baker, I loved Tom Baker, everyone did, but the Doctor these days has taken on a sort of rock star status.

Did you enjoy filming in Cardiff?
Brilliant, it was lovely. It was a fantastic journey out of Cardiff down to the studio – a really beautiful part of Wales. We filmed in an amazing Victorian castle looking right out on the Gower peninsular. It was absolutely stunning.

What will you be doing on Christmas day?
Entertaining children, trying to keep a lid on sugary treats and desperately rationing presents because our children got high on them last year. Also, we will of course be watching Doctor Who. I really hope it’s another cold Christmas; I loved the cold winter last year. A bit of snow and a bit of sledging – it’ll be great.