To clarify. I've been commissioned to write two episodes of 'Doctor Who'. That doesn't mean they'll both necessarily be in this season.

— Mark Gatiss (@Markgatiss) March 27, 2014

Mark Gatiss is already responsible for writing six Doctor Who episodes: Cold War, The Crimson Horror, Night Terrors, Victory Of The Daleks, The Idiot's Lantern and The Unquiet Dead. But whilst talking with the press as part of the BBC Worldwide Showcase in Brazil he has confirmed he will be adding two more to that tally.Gatiss told Brazilian website CBN Foz : “I am writing for Peter Capaldi – two episodes, in fact.”It's no massive surprise but still good to have confirmation of his return. Gatiss has got more and more involved with Doctor Who recently, 2 episodes last year and 2 episodes this year, surely he's the number one contender to take over as show runner when Steven Moffat leaves. What do you think?Source: CBN Foz (via Google Translate!!)UPDATE 27/3Mark Gatiss posted this to Twitter todayPersonally, I would still think it's likely they will both be this series.