It will be a family Christmas for the Time Lord when he is reunited with his wife Professor River Song for the Doctor Who festive special.
Alex Kingston will reprise her role as the time-travelling archaeologist in BBC1's sci-fi series, in which she meets her husband's new incarnation - played by Peter Capaldi - for the first time.
"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," Kingston said.
The actress, who made her first Doctor Who appearance in 2008 and has appeared in 15 episodes to date, is filming the Christmas special in Cardiff alongside Capaldi and showrunner Steven Moffat.
"I met Peter 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!" Kingston said.
The star, whose other screen credits include American medical drama ER and US superhero series Arrow, continued: "Steven Moffat is on glittering form, giving us an episode filled with humour and surprise guest castings."
Moffat, who wrote the festive instalment, said: "Another Christmas, another special for Doctor Who - and what could be more special than the return of Alex Kingston as Professor River Song."
He teased: "The last time the Doctor saw her she was a ghost. The first time he met her, she died. So how can he be seeing her again? As ever, with the most complicated relationship in the universe, it's a matter of time..."
Other guests joining Capaldi and Kingston will be revealed over the coming months.
The new series of Doctor Who will return to BBC1 for 12 episodes from September 19, followed by the Christmas special on Christmas Day.