David Bradley

David Bradley (born in Yorkshire, England) has several credits in and related to the DWU. Most notably, he portrayed William Hartnell, who played the First Doctor and originated the part of the Doctor, in the docudrama An Adventure in Space and Time. He would later portray the First Doctor himself in a surprise appearance in The Doctor Falls.

Prior to this, he provided the voice of the Shansheeth in The Sarah Jane Adventures story Death of the Doctor and Solomon in Dinosaurs on a Spaceship during Series 7 of Doctor Who. Like Colin Baker and Peter Capaldi before him, he has played the Doctor in the TV series proper after having previously held another role on the show. 

Outside of the Doctor Who franchise Bradley is known for, among other things, , written by Chris Chibnall, and for playing Argus Filch in the Harry Potter movies and Walder Frey in the HBO series Game of Thrones.