The Doctor (Doctor Who)
Jodie Whittaker took over the role as the Thirteenth Doctor in the 2017 Christmas special. In addition to the above-listed actors, others have played versions of the Doctor for the duration of particular storylines.
Notably, John Hurt guest starred as the War Doctor in the closing moments of the 2013 episode "The Name of the Doctor", the webcast "The Night of the Doctor" and the 50th Anniversary episode "The Day of the Doctor". The War Doctor is an incarnation existing between those of McGann and Eccleston. Hurt was never the programme's lead actor; his Doctor was retroactively inserted into continuity for the programme's 50th anniversary, and was written so as not to disturb the ordinal naming of the established Ninth, Tenth and Eleventh Doctors. In the 1986 serial "The Trial of a Time Lord", Michael Jayston played the Valeyard, an amalgamation of the Doctor's darker sides from between his twelfth and final incarnations.
Mark Williams (actor)
Mark Williams (born 22 August 1959) is an English actor, screenwriter and presenter. He is best known as Arthur Weasley in the "Harry Potter" films, and as one of the stars of the popular BBC sketch show "The Fast Show". He also played Brian Williams in the BBC series "Doctor Who", and Olaf Petersen in "Red Dwarf". More recently he has appeared as the title character in the BBC series "Father Brown".