Sherlock fans treated to behind-the-scenes video ahead of third series

Cast and crew offer some hints as to what viewers can expect

Fans of BBC detective drama Sherlock have been treated to a behind-the-scenes video ahead of Benedict Cumberbatch’s return to the lead role tomorrow night.

Scroll down to see the video

The first episode of the third series, "The Empty Hearse" will air on New Year’s Day at 9pm, starring Martin Freeman as Holmes’ sidekick John Watson.

Viewers are expecting Sherlock’s death in second series finale "The Reichenbach Fall" to be explained as preview clips and pictures have already shown the crime-solving hero alive and back in action.

“We know that there’s got to be a reckoning of how he did it. We’ve all seen it – John’s seen it – he’s just jumped off the roof of Bart’s, and yet he’s alive,” says Freeman.

"More interestingly than the how is the why, the meat on those bones of Sherlock having been away and how he comes back. It’s dangerous emotionally and it’s dangerous physically as he knows John will be immensely upset."

In the behind-the-scenes video, the cast and crew offer some hints about the forthcoming series. Steven Moffat, co-creator and writer, gushes about the scene in which John and Sherlock are reunited.

"It goes on for a long time and I have watched it many, many times and I absolutely love it," he says, while co-creator Mark Gatiss adds that it "makes (his) hair stand on end, it’s so beautifully played".

Cumberbatch speaks about his part as Sherlock, describing his character’s third series journey as one of "reassimilation". "It’s very much from a point of view of learning and adjusting to being brilliant, to having to confront something which points out that he is frail, that he is human, with weakness and vulnerability," he explains.

"Sherlock comes back to a world he expects to be exactly the same and discovers that…nothing will be the same," Gatiss closes, leaving fans still in plenty of suspense.

Actress and real-life partner of Martin Freeman, Amanda Abbington, spoke to The Independent yesterday about landing her role as Watson's new wife Mary.

"Mark and Steven thought it would be easy for Martin to play opposite me and that we would have a natural shorthand together – how wrong they were!," she said.