The real life mother and daughter duo are set to play the same relationship in Doctor Who, with their characters holding a dark secret.
The episode features Matt Smith, incoming companion Jenna Louise-Coleman and will be directed by Saul Metzstein.
Dame Diana Rigg, who will play a Yorkshire local, says: “The first time Rachie and I will be working together is on an episode of Doctor Who specially written for us by Mark Gatiss. How lucky is that?”
Rachael Stirling, on working on Doctor Who, said: “What joy. I am looking forward to the madness of Doctor Who enormously. Mark Gatiss has written a gift of a script and an on-screen relationship between Ma and I that is truly delicious. We have never before worked together because the offers have not been tempting, but when such a funny and original script comes through you know the time has come.”
Steven Moffat, executive producer and head writer on Doctor Who, says: “Dame Diana Rigg, Rachael Stirling and a Mark Gatiss script - a combination of talents you could only get in Doctor Who. Frankly, I'm terrified already!"
Production on the story will began today at the BBC's Roath Lock studios in Cardiff.
(Source: BBC Media Centre, Doctor Who Blog)