‘Sherlock’ fans were left with speculations after a promotional image of Holmes and Watson wearing classic Victorian clothes was revealed.

Instead of the typical contemporary setting of the series, the photo showed the original setting for the detective as envisioned by Sir Arthur Conan Doyle, writer of the ‘Sherlock Holmes’ detective stories.

The rumors further increased when the BBC show’s stars, Benedict Cumberbatch and Martin Freeman, were seen recently as they were filming wearing Victorian costumes.

To some extent, rumors about future ‘Sherlock’ episodes can be confirmed as series writer Steven Moffat announced several details about the upcoming special of the TV crime drama series.

In an interview with Entertainment Weekly, Moffat emphasized the importance of such special 90-minute episode in contributing to the storyline.

“The special is its own thing. We wouldn’t have done the story we’re doing, and the way we’re doing it, if we didn’t have this special,” Moffat explained.

The TV writer also stated that production is almost complete and that he is pleased with the outcome when it comes to the Victorian era episode. Moffat has been widely recognized for doing an impressive job in switching between time periods, having worked on many ‘Doctor Who’ episodes.

With its mischievous storylines and witty humor, ‘Sherlock’ has gained considerable popularity and sustained numerous positive reviews from the first to the third season. Following the show’s debut in 2010, Cumberbatch easily stood out from the crowd of British stars and bagged leading roles in ‘Star Trek: Into Darkness’ and the upcoming ‘Doctor Strange’ film from Marvel.

The 38-year-old actor was also nominated for an Oscar, thanks to his impressive performance in ‘The Imitation Game.’

Cumberbatch will reprise his detective role and continue solving difficult cases in the fourth season of ‘Sherlock’, which is expected to debut in 2016 after the airing of the special episode this December.

Meanwhile, fans can look forward to a better season four as Moffat shared that they have big plans for the series in the forthcoming episodes.

"We have a plan to top [Season 3]," Moffat said. "And I do think our plan is devastating. We’ve practically reduced our cast to tears telling them the plan … we’re probably more excited that we’ve ever been about Sherlock."

In the fourth season, fans will also get to see Watson as a father after being married to Mary Morstan, who was last seen pregnant in the third season. The women are expected to play more roles in the upcoming season while the possibility of Sherlock and Molly ending up together will also be something to look forward to.