Well...here we go again...
The official Doctor Who website has confirmed reports that Peter Capaldi will leave his role of the Twelfth Doctor in the 2017 Christmas Special, making his run four years to the day since his full debut replacing Matt Smith at the very end of "The Time of the Doctor" on Christmas Day, 2013. The 2017 Christmas Special will also be the last for series executive producer Steven Moffat, who will turn control of the series over to incoming showrunner Chris Chibnall for Series Eleven in 2018.
Making the announcement on Jo Whiley's BBC Radio 2 show earlier today, Capaldi said "One of the greatest privileges of being Doctor Who is to see the world at its best. From our brilliant crew and creative team working for the best broadcaster on the planet, to the viewers and fans whose endless creativity, generosity and inclusiveness points to a brighter future ahead. I can’t thank everyone enough. It’s been cosmic."
Capaldi made a very brief appearance as the Twelfth Doctor in the show's 50th anniversary special "The Day of the Doctor" in 2013 and previous appeared as Lobus Caecilius in the 2008 David Tennant era story "The Fires of Pompeii". He also appeared as John Frobisher in the Doctor Who spinoff Torchwood: Children of Earth.
Moffat remarked, "For years before I ever imagined being involved in Doctor Who, or had ever met the man, I wanted to work with Peter Capaldi. I could not have imagined that one day we’d be standing on the TARDIS together. Like Peter, I’m facing up to leaving the best job I’ll ever have, but knowing I do so in the company of the best, and kindest and cleverest of men, makes the saddest of endings a little sweeter. But hey, it’s a long way from over. Peter’s amazing, fiery, turbulent Doctor is still fighting the good fight, and his greatest adventures are yet to come. Monsters of the universe, be on your guard -- Capaldi’s not done with you yet!"
Executive producer Brian Minchin said, "Peter Capaldi is an extraordinary Doctor and has taken the show to amazing places. Although I'm sad he has decided to move on in 2018, I'm delighted that we have one final series with Peter Capaldi and Steven Moffat. I know what they're planning and it's going to be incredible."
Capaldi will be joined by new companion Pearl Mackie (Bill Potts) and Matt Lucas (Nardole), with guest appearances to come from David Suchet and Michelle Gomez (Missy/The Mistress).
Doctor Who will return to BBC America for Series 10 on April 15, 2017.