Mark Gatiss, co-creator and star on television show Sherlock said that fans will witness an "expected tragedy" in its upcoming season with RadioTimes on Thursday.

The BBC One drama, which stars Benedict Cumberbatch in the title role and Martin Freeman as Dr. John Watson, is a modern take on the Sherlock Holmes literature series written by Sir Arthur Conan Doyle, narrating the life of the "consulting detective" and his war veteran friend. Gatiss stars as Mycroft Holmes', Sherlock's older brother, on the show.

“You can always expect tragedy as well as adventure, that’s just how it goes," Gatiss said to RadioTimes.

Gatiss did not say as to what this tragedy was per say, however it has been hinted by Freeman that Watson's wife Mary will be killed off, who is played by Freeman's real-life partner Amanda Abbington on the show.

“While we play fast and loose with the original stories, we generally follow the trajectory of what Conan Doyle did," Freeman said to Telegraph. "So [Watson] gets married, and then Mary dies - so at some point presumably she’ll die."

In the Doyle original short story "The Adventure of the Norwood Builder," Mary dies of unknown causes and Watson is left to rejoin Holmes at their residence on Baker Street.

However Gatiss urges fans and viewers to not assume the worst.

"Just because it’s in the stories doesn’t mean it’ll happen in the series because there’s an awful lot of changes and an awful lot of places to go and things to do," he said.

Gatiss co-created the Emmy-winning television show with Steven Moffat, who is also famous for writing the current rendition of Doctor Who, another BBC show. The show has earned both Cumberbatch and Freeman an Emmy award for their portrayals of the detective duo, as well as Cumberbatch being nominated for a Golden Globe for the role in 2013.

Sherlock season four begins filming in January 2015 for a possible premiere date later in the year.

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