SFX claims that the instalment, which will air fourth in the next run, is entitled 'The Doctor's Wife'.
Former Coronation Street actress Suranne Jones will appear in the episode as Idris, previously described by Gaiman as "an old acquaintance with a new face".
Michael Sheen will voice a character in the instalment, which also stars Elizabeth Berrington and Adrian Schiller.
Gaiman recently revealed that he is "happy" with the final version of his script, adding: "They spent money on this one and it shows."
Doctor Who will return to BBC One in April.
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Watch the new Doctor Who prequel below: