Little Nell

Little Nell was a fictional character created by Charles Dickens. On Christmas Eve 1869, the Ninth Doctor told Dickens that her death scene "cracked [him] up". (TV: The Unquiet Dead)

Conversely, Henry Gordon Jago told his friend Professor George Litefoot in the 1890s that he was "beside [himself] when Little Nell died." (AUDIO: Beautiful Things)

Behind the scenes
The mention of this character implied that the novel,, also exists within the Doctor Who universe.