"The Husbands of River Song" is an episode of the British science fiction television series Doctor Who. First broadcast on BBC One on 25 December 2015, it is the eleventh Christmas special since the show's revival in 2005. It was written by Steven Moffat and directed by Douglas Mackinnon. The episode marks the return of Alex Kingston as River Song, making her first appearance alongside Peter Capaldi's Twelfth Doctor and her last on-screen appearance to date. This also features the first appearance of Nardole, who would become a companion starting from the next episode.

In the episode, the alien time traveller known as the Doctor encounters River Song on the colony of Mendorax Dellora in 5343, with one of her husbands, Hydroflax (Greg Davies), who has an invaluable diamond lodged in his brain. Outsmarting Hydroflax and his worshippers, the Doctor and River have a date at the Singing Towers of Darillium, which the Doctor knows will be the last meeting before her death.

After the dark ending of series 9, Moffat wrote "The Husbands of River Song" to have a lighter tone. The episode was filmed in September 2015. In addition to airing on Christmas Day, the episode received cinema airings in several countries. In the UK, the episode was watched by 7.69 million viewers. "The Husband of River Song" was met with generally positive reviews; critics particularly praised the chemistry between Capaldi and Kingston, but were unsure of the comedic tone of the episode.