Fans of BBC's hit series 'Sherlock' are in luck as reports are claiming production for the fourth season is set to start in Spring 2016. While the Christmas Special is set to air this year, what fans are really waiting for is the next installment of the show.

For those that may not know, the upcoming Christmas special is Sir Arthur Conan Doyle's short story "The Adventure of the Blue Carbuncle." It will showcase Sherlock and Dr. Watson working hard on a mystery about a convicted plumber accused of stealing a rare and valuable gem.

While the special is only one episode in length, it's still expected to be a great start to 'Sherlock' Season 4. However, as it stands, there is no official release date stated for any new episodes after that.

Stepping into the special episode set to air Christmas day, viewers will see the episode take place in the 1890s where the characters will be seen in Victorian style clothing.

Showrunner Steven Mofatt said in an interview on the matter, "We've got, I think you can safely say, the Sherlock Holmes and Dr. Watson of a generation - we want to see them do it in the proper outfits, just once,"

Moving back to the fourth season of the show, Den of Geek speculates that since filming and production starts in Spring 2016, the release date is expected to be sometime in January of 2017. However, that is near or there as release dates that far are always subject to shifts and changes.

Moreover, Moffatt went on to talk about what fans can expect with 'Sherlock' Season 4. He said, "It's dark in some ways-obviously it's great fun and a Sherlock Holmes romp and all that-but there's a sense of... things... coming back to bite you. It's not a safe, sensible way to live. It's hilarious and exhilarating some days, but some days it's going to be bloody frightening,"

Check out the official trailer for the 'Sherlock' Christmas Special below: