"The Day of the Doctor" is a special episode of the British science fiction television programme Doctor Who, marking its 50th anniversary. It was written by Steven Moffat, who served as an executive producer alongside Faith Penhale. It was shown on BBC One on 23 November 2013, in both 2D and 3D. The special was broadcast simultaneously in 94 countries, and was shown concurrently in 3D in some cinemas. It achieved the Guinness World Record for the largest ever simulcast of a TV drama and won the Radio Times Audience Award at the 2014 British Academy Television Awards.

The War Doctor is an incarnation of the Doctor, the protagonist of the British science fiction television programme Doctor Who. He was portrayed by the English actor John Hurt. Although he precedes Christopher Eccleston's Ninth Doctor in the show's fictional chronology, his first onscreen appearance came eight years after Eccleston's; the War Doctor was retroactively created by showrunner Steven Moffat for productions celebrating the show's 50th anniversary. Hurt would reprise the role in the 2015 audio drama series The War Doctor until his death in 2017, with actor Jonathon Carley taking over the role from 2020 onward.