It was confirmed by Douglas Mackinnon himself on his Twitter account that he’ll be directing a Sherlock episode. He didn’t specify which one, but considering what he tweeted, it could be the 2015 special that writer/actor Mark Gatiss mentioned before.
Mackinnon, whose first Doctor Who story was 2008’s “The Sontaran Strategem” and who went behind the camera on no fewer than three of Doctor Who’s series eight episodes (Listen, Time Heist and Flatline) beat around no bushes with the Twitter announcement, which simply read:
Next job, directing Sherlock.
— Douglas Mackinnon (@drmuig) November 5, 2014
Last we heard, the Sherlock special is being written by Gatiss and Steven Moffat and is planned to start shooting this coming January. No date has been announced for the airing of the special.