The 26-year-old star will return to the BBC sci-fi drama in this year's Christmas special, having previously made a surprise appearance in the episode 'Asylum of the Daleks'.
Coleman will play a character named Clara in the episode, it was confirmed last night (November 16).
The 2012 Doctor Who festive episode - titled 'The Snowmen' - will feature guest appearances from Richard E Grant (Withnail & I) and Tom Ward (Silent Witness).
Of new cast addition Coleman, Moffat previously told Digital Spy: "She brings a kind of speed, a wit, a sort of unimpressed-ness which has the Doctor (Matt Smith) dancing a little harder than he's used to."
Fellow Who writer Tom MacRae also described the actress as "fantastic" in an interview with DS.
"She just had this amazing energy," said MacRae. "She's actually a couple of years older than Karen [Gillan] but she seems younger - she seems more of a teenager and bouncy."
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