On this Christmas Special Steven Moffat said:
“Oh, we're going for broke with this one. It's all your favourite Christmas movies at once, in an hour, with monsters and the Doctor and a honeymoon and – oh, you'll see. I've honestly never been so excited about writing anything. I was laughing madly as I typed along to Christmas songs in April. My neighbours loved it so much they all moved away and set up a website demanding my execution. But I'm fairly sure they did it ironically.”
Controller of the BBC, Ben Stephenson said:
“Matt Smith and Karen Gillan captivated audiences in their debut series and Doctor Who's clever twist on the much loved A Christmas Carol will thrill BBC One viewers this year with special guest stars Sir Michael Gambon and singing sensation Katherine Jenkins joining Amy and the Doctor for an unforgettable present!”
Katherine Jenkins said:
“I'm over the moon to be involved in the Doctor Who Christmas Special – I can't quite believe it as it's a part of the family tradition at the Jenkins household. I heard the news that I got the role on my 30th birthday and it was the best birthday present ever!”
The full BBC Press release can be read here but contains spoilers for any those who haven’t seen episodes thirteen of series five; The Big Bang. Filming is currently happening in Cardiff and will continue into August followed by filming for Matt Smith’s second series as the Doctor.