Colm McCarthy, the man in the director's chair for Doctor Who Easter special The Bells of Saint John, is to helm Sherlock season three episode The Sign of Three, the second instalment in the upcoming series.
McCarthy has a background in detective shows, having worked on episodes of BBC1's period crime drama Ripper Street as well as ITV's Inspector Morse prequel Endeavour. He was signed up for Sherlock following the departure of director Paul McGuigan, who is credited with having set the distinctive visual template for the programme.
The Sign of Three is written by Steve Thompson, who also penned series one story The Blind Banker and season two finale The Reichenbach Fall. The title is a play on that of original Sherlock Holmes story The Sign of Four, with the episode teasingly referred to as the "wedding" story by Sherlock creators Mark Gatiss and Steven Moffat, leading to speculation that it could see Martin Freeman's John Watson meet his future wife.
Shooting on series three of Sherlock – which stars Benedict Cumberbatch as the great detective – is currently under way, with the first two of three 90-minute episodes set to be completed before a summer break.
Susie Liggat and Sue Vertue will produce The Sign of Three.
Series three of Sherlock is due to air towards the end of the year.