David Tennant, David Bradley, and David Morissey have all played the role of the Doctor from Doctor Who, David Tennant as the Tenth Doctor from 2006-2010, David Morissey in The Next Doctor, and David Bradley playing William Hartnell as the First Doctor in An Adventure in Time and Space.
The trivia item below may give away important plot points.
This series takes place in the small town of Blackpool. Blackpool is where Jenna Coleman (Clara Oswald, Doctor Who) was born and raised. She costarred with David Tennant ( D.I. Peter Carlisle) in the multiDoctor episode The Day of the Doctor, where Tennant played the Tenth Doctor.