Orla Brady will feature in the Doctor Who Christmas special - Matt Smith's final outing as the Timelord.
The LA-based Dublin actress has featured in several hot shows on both sides of the Atlantic, ranging from the UK mainstream hit Mistresses to cult US sci-fi favourite Fringe.
Most recently, she featured alongside David Suchet in the final season of the hugely popular ITV drama Poirot, based on the character created by Agatha Christie.
According to Digital Spy, Brady's character in the Doctor Who Christmas special is someone from the Doctor's past, and the plot of the festive episode will revolve around her.
Smith's final appearance as the 11th Doctor is also expected to feature classic Who villains The Cybermen.