"The 12 Days of Christine" is the second episode of the second series of British black comedy anthology series Inside No. 9. It first aired on 2 April 2015 on BBC Two. It was written by Steve Pemberton and Reece Shearsmith, and directed by Guillem Morales. The episode tells the story of Christine, a young woman living in a small flat, over 12 years in her life, focussing on key days and life events in that time. Christine is played by Sheridan Smith, while those who play an important part in her life are played variously by Tom Riley, Stacy Liu, Michele Dotrice, Paul Copley, Pemberton, Jessica Ellerby, Joel Little and Dexter Little. Shearsmith plays the Stranger, an unknown figure apparently haunting Christine.

Inside No. 9 is a British black comedy anthology television programme that first aired on 5 February 2014. It is written by Steve Pemberton and Reece Shearsmith and produced by the BBC. Each 30-minute episode is a self-contained story with new characters and a new setting, almost all starring Pemberton or Shearsmith. Aside from the writers, each episode has a new cast, allowing Inside No. 9 to attract a number of well-known actors. The stories are linked only by the number 9 in some way, typically taking the form of a door marked with the number 9, and a brass hare statue that is in the background of all episodes. Themes and tone vary from episode to episode, but all have elements of comedy and horror or perverse humour, in addition to a plot twist. Pemberton and Shearsmith took inspiration for Inside No. 9 from an episode of Psychoville, a previous project, which was filmed in a single room – this in turn was inspired by Alfred Hitchcock's Rope.