Excluding his brief cameo in the 50th anniversary special “The Day of the Doctor,” Peter Capaldi made his full Doctor Who debut in the 2013 Christmas special “The Night of the Doctor,” succeeding Matt Smith, a.k.a. the Eleventh Doctor.
Season 8 of the Doctor Who revival, kicked off in August 2014, and he’s been traveling in the TARDIS ever since.
They’ll also be accompanied by Nardole, played by Matt Lucas, who has appeared in the past two Christmas specials.
During his first two seasons, Capaldi’s Doctor traveled around with Jenna Coleman’s Clara Oswald, but starting with Season 10, his new companion will be Bill, played by Pearl Mackie.