Game of Thrones star Kit Harington is teaming up with Sherlock co-creator Mark Gatiss to adapt Arthur Conan Doyle's Christmas horror story, "Lot No. 249".

Harington, best known for his portrayal of Jon Snow, is set to appear in a holiday movie, based on the Victorian short story. Deadline states that Gatiss has adapted "Lot No. 249" for the annual BBC series of holiday horror stories, "A Ghost Story for Christmas".

In the film, Harington will take on the role of Oxford athlete Abercrombie Smith who suspects fellow student Edward Bellingham, played by Freddie Fox, of using an Egyptian mummy, called Lot No. 249, to terrorize his enemies.

Gatiss expresses his enthusiasm about delving into another one of Arthur Conan Doyle's works, saying "Lot No. 249" is a favorite of his. Emphasizing the story as an "end-of-empire chiller", Gatiss comments on the suspenseful narrative filled with intense scares.

This 1892 classic also marks Gatiss's return to Doyle's literature. Prior to this, Gatiss adapted Doyle's Sherlock Holmes stories into the iconic modern-day BBC series Sherlock, featuring Benedict Cumberbatch, between 2010 to 2017.

"Lot No. 249" was Doyle's contribution to the wave of "Egyptomania" that swept over Europe, marking the first literary introduction of a lethal mummy antagonist. The upcoming adaptation sort of serves as a mini Game of Thrones reunion, as Gatiss had a role on the HBO fantasy series himself, where he interacted with Jon Snow, Harington's character. The air date for "Lot No. 249" is set for Christmas on BBC Two, with its North American broadcast details remaining unknown.