Holmes' arch-nemesis Jim Moriarty will return for the Sherlock season 4 Facebook/Sherlock

Sherlock, the hit BBC One drama, will return to screens for a Sherlock Christmas Special episode , followed by a new series in 2016.

The exact date for the slated 2016 season 4 premiere of the detective show is still held questionable as cast members are getting their hands full with other projects.

Earlier, producer Sue Vertue had assured fans saying: "We're working on it. We're working on dates." Meanwhile, her husband and co-producer Steven Moffat said: "We'll get them made as quickly as we can."

Furthermore, Moffat's co-creator and co-show runner, Mark Gatiss, who also plays 'Mycroft Holmes' in the show, said they have "moved significantly closer to getting a date in the diary for series four," according to a report by Radio Times.

The latest rumours on Sherlock suggest that Holmes' archnemesis Jim Moriarty will return for the upcoming season. And there are speculations that Moriarty's return could be caused by none other than his ever-growing obsession with the detective played by Benedict Cumberbatch.

Meanwhile, Irish actor Andrew Scott said he was quite surprised with how the fans went through the lengths of portraying the relationship between the detective and the villain as something more "romantic" in their fan-fictions.

"Oh my god, it's the drawings and the photos!" he said.

"It's mostly women doing it. You're put with quite an array of different people. I think it's done by librarians," he added.

Amidst the crazy and explicit fan fictions, the 37-year-old star gave thoughts about the dynamics of the relationship his character shared with the protagonist.

"Well, they are absolutely obsessed with each other," he told Attitude magazine.

"There has to be a line. In the words of Erasure, I love to hate you," Scott added.

Showrunners Moffat and Gatiss further shed light to the rumours surrounding the return of Moriarty.

"We've had what we're going to do with Moriarty in place from before the second season. Exactly what we're going to do. I remember talking it through with Andrew Scott, who plays Moriarty. Wait and see what's going to happen," Moffat said.

Previously, Co-creator, writer and executive producer Mark Gatiss said : "Series Four! At last ! It's always special to return to Sherlock but this time it's even more special as we're doing... a Special! Not only THAT, we'll then be shooting three more episodes which will take Sherlock and John Watson into deeper and darker water than ever before. The whole Sherlock team are terrifically excited to return for four new adventures. The Game is on - again!"