Lead writer/Executive Producer Steven Moffat said:
"It's a testament to the quality of Peter Harness's intense and emotional script, that we've been able to attract an actress of the brilliance of Hermione Norris. And for the first time since 1984, the Doctor Who production team is heading to Lanzarote. The Doctor is returning to the scene of an old adventure - but there have been sinister changes since his last visit."Norris said:
"It's exciting to be part of such an iconic show, and one that my kids can watch!!!"
The actress has had a number of memorable roles on television, including Ros Myers in Spooks, Beatrice in Kingdom, and DCI Carol Jordan in Wire in the Blood; her sci-fi credentials include playing Stella Isen in Outcasts. She can currently be seen in the BBC drama The Crimson Field.
Also announced for this episode is Tony Osoba, joining the relatively small 'club' of actors to appear in both the 'classic' and new series of Doctor Who. This will be his third appearance (and Doctor!) in the series: the actor previously appeared as the Movellan Lan in fourth Doctor adventure Destiny of the Daleks and as Kracauer in seventh Doctor tale Dragonfire.