Are you guys ready?
It's . . .
THE DOCTOR'S WIFE!
However, in this episode, River Song (played by Alex Kingston, and the one we all think is the Doctor's wife but may turn up to be someone completely unexpected) is nowhere to be seen and instead we have a mysterious character called Idris, played by Suranne Jones (Coronation Street, Single Father).
About Idris, SFX reports:
In a column for Doctor Who Magazine, Gaiman described Suranne’s character as “someone who is beautiful, and who bites, and who might just turn out to be an old acquaintance with a new face…”, adding, “it starts in void-space, with something – or someone – we have not seen since [1969 Patrick Troughton story] ‘The War Games’, and a knock on the TARDIS door…”
Actor Michael Sheen (Underworld, Tron: Legacy) will also voice a character in this episode.
Will it end up being another not-as-simple-as-it-seems episode like The Doctor's Daughter or will Idris TRULY be, the Doctor's Wife?