Fans of the long-running British science fiction show have long been gripped with the following question: Who is the Thirteenth Doctor? The 12th Doctor Who is played by Peter Capaldi but the BBC confirmed several months back that once his run was over, it was going to pick out a new actor to play Doctor Who as is the norm with this series. The BBC has finally confirmed who is going to be the 13th Doctor. Doctor Who is centered around the story of the Doctor who can travel through time and space in a time machine called the TARDIS. The time machine is shaped like the 1920s British police box.