David John Bradley is an English actor. He is known for playing Argus Filch in the Harry Potter film series, Walder Frey in the HBO fantasy series Game of Thrones, Abraham Setrakian in the FX horror series The Strain, and for voicing Merlin in Guillermo del Toro’s animated Netflix series Tales of Arcadia (for which he won an Annie Award for Best Voice Actor in a Television Series). He is also an established stage actor, with a career that includes a Laurence Olivier Award for his role in a production of King Lear. In 2012, Bradley played Solomon in the Doctor Who episode "Dinosaurs on a Spaceship". In 2013, he portrayed William Hartnell, the actor who played the First Doctor, in the Doctor Who docudrama An Adventure in Space and Time. He returned to Doctor Who in 2017, appearing as the First Doctor in "The Doctor Falls" and "Twice Upon a Time". Since January 2018, he has reprised the role in a series of audio stories released by Big Finish entitled The First Doctor Adventures.