Crossover

A crossover character is a character who exists both within the Doctor Who Universe and one or more other fictional universes. Although, within the Doctor Who Universe, fictional characters have appeared as such (within the Land of Fiction, for example), characters from other works have, from time to time, from other continuities gotten involved.

Throwaway lines alluding to other fictional universes are more common than actual appearances of characters from those universes.

Television examples
So far, only one major crossover has occured in televised Doctor Who, when the the Doctor and some of his companions met the cast of EastEnders in Dimensions in Time (which is generally not regarded as part of the canon, despite John Nathan-Turner's intention that it should be).

Of course, EastEnders is fiction in the Doctor Who Universe, as revealed in Army of Ghosts, just as characters like the Doctor and the Daleks are fictional in the continuity of EastEnders.

Comics examples

 * When Marvel UK owned Doctor Who Monthly, later Doctor Who Magazine, characters like Death's Head, Keepsake, and the Special Executive would cross over between Marvel UK titles. (Marvel USA occasionally made oblique references to Doctor Who - the X-Men spin-off Excalibur featured the Weird Happenings Organisation, led by Brigadier Alistaire Stewart.)


 * The 2000AD strip Caballistics, Inc., which features Doctor Who references so frequently they are practically part of the series' format, once depicted a character clearly intended to be the actor Tom Baker being murdered by Scottish nationalist demons. (This undermines the frequent suggestion by Caballistics, Inc fans that the series is unofficially set in the Doctor Who universe.)

Prose fiction examples

 * The Old Ones originated in the Cthulhu Mythos, which pre-dated Doctor Who.


 * Iris Wildthyme originated in the independent works of Doctor Who novel writer Paul Magrs.


 * Sherlock Holmes and Doctor John Watson appeared as themselves in NA: All-Consuming Fire where they are established as real. (In the Doctor Who Universe, they do not actually use the names Sherlock Holmes and Watson, but use these as aliases.)


 * Carnell, the psychostrategist featured in Chris Boucher's novel Corpse Marker, first appeared in the Blake's 7 TV episode Weapon (where he was portrayed by Scott Fredericks).


 * Lady Jennifer Buckingham from The War Games briefly appears in the second volume of Kim Newman's crossover-intensive Anno Dracula series. Charles Beauregard, the hero of several Anno Dracula stories, is referred to in All-Consuming Fire.