Series 9 of Doctor Who hasn’t even started airing yet, but that hasn’t stopped the BBC from revealing the surprising and significant guest star of this year’s Christmas Special – Alex Kingston’s Professor River Song!

“It’s Christmas Day in the future and the TARDIS is parked on a snowy village street, covered in icicles, awaiting its next adventure,” says the blurb on the BBC website. “Time traveller River Song meets her husband’s new incarnation, in the form of Peter Capaldi, for the first time this Christmas.”

The announcement of a new River story is always a bit of a surprise for fans, who can never be sure when the enigmatic archaeologist is going to pop up again – and it appears they’re not the only ones!

“To be honest, I did not know whether River would ever return to the show, but here she is, back with the Doctor for the Christmas special,” said Kingston.

“I met Peter [Capaldi] for the first time at Monday’s read through, we had a laugh, and I am now excited and ready to start filming with him and the Doctor Who team. Christmas in September? Why not!”

The special, which begins filming in Cardiff this week, will be written by Steven Moffat, produced by Nikki Wilson and directed by Douglas Mackinnon. Set to air in the UK on 25 December 2015, it will be followed in January by ‘The Diary of River Song’ – River’s very own audio series from Big Finish Productions.