Daleks to invade Buckingham Palace QUIZ: How well do you know Doctor Who? The series celebrates its 50th birthday later this month with a TV drama about the early days of the show called An Adventure In Space And Time, followed by an anniversary episode on November 23 called The Day of the Doctor with the current Doctor, Matt Smith, as well as his predecessor David Tennant. Smith's stint as the Time Lord ends this year when he will be replaced by Peter Capaldi, best known for his role as the spin doctor Malcolm Tucker in the BBC series The Thick of It. The Countess will also meet young competition winners from two schools in South Wales where scenes from the 50th episode were filmed. The children will show Sophie their winning drawings of "The Queen's TARDIS." Doctor Who holds the Guinness World Record for the longest running science fiction series in the world. It began on 23 November 1963, starring William Hartnell as the Doctor and there have been 11 Doctors to date.