It’s official! Filming has begun on the 2015 Christmas special of Sherlock.

The hit BBC detective show stars Benedict Cumberbatch and Martin Freeman as Sherlock Holmes and Dr John Watson respectively, in a modernised reboot of the classic Conan Doyle canon.

The cast and crew returned to work this week in London, filming a brand new episode of the critically-acclaimed show in Bristol. People gathered outside Colston Hall to catch a glimpse of the pair filming, who were sporting traditional style Holmes and Watson Victorian attire. (photo gallery here)

Writer Mark Gattis let the cat out of the bag on Monday, tweeting: “On my way West. It begins… #Sherlock.”

Fans of the popular series – penned by Doctor Who head writers Gatiss and Steven Moffat – have been warned to not get to excited however, with Series 4 not due until at least 2016.

The holiday-themed Christmas day special is currently in production and is expected to feature Sherlock’s arch nemesis Moriarty (Andrew Scott), with an explanation well over due as to how he managed to shot himself in the face and seemingly survive. However, stranger things have happened – think Sherlock’s revival after The Reichenbach Fall.

Filming has come as a welcome distraction for Cumberbatch, as news breaks that the 38-year old star and his new fiancée, actress Sophie Hunter, are expecting their first child later this year.