The Doctor, the Widow and the Wardrobe (in-universe)

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You may be looking for the real-world TV episode.
The back cover of the Series 7 DVD boxset. (COMIC: The Girl Who Loved Doctor Who)

The Doctor, the Widow and the Wardrobe was a Christmas episode of the television series, Doctor Who, starring the Eleventh Doctor. It featured snow, presents, and monsters, and was described by the Doctor, in a letter to the readers of Doctor Who Adventures, as his "most Christmassy Christmas episode yet". (PROSE: Hello, Time Travellers!)

The episode also existed in a parallel universe, in which it was the first episode of Series 7, and was included on its DVD boxset release. (COMIC: The Girl Who Loved Doctor Who)