A couple of details on Mark Gatiss’ Series 7 episode have been confirmed in the latest issue of Doctor Who Magazine.

Gatiss previously penned episodes The Unquiet Dead, The Idiot’s Lantern, Victory of the Daleks and, more recently, Night Terrors.

His new episode is directed by Douglas Mackinnon and will guest star veteran actor David Warner, alongside Liam Cunningham.

Warner, last seen on TV screens in Mad Dogs, has actually worked on Doctor Who before. He voiced Lord Azlok in the animated Dreamland mini-series starring David Tennant. He has also lent his voice to several Big Finish audio dramas.

Cunningham, meanwhile, appears to be on a bit of a cult TV spree at the moment. He was recently in Game of Thrones and is set to appear in Merlin later this year.

No other clues on the story were revealed except to say it will be “massive.” Although there been some reports that the episode might a deep sea adventure taking place on a submarine.

Below: David Warner on Dreamland.