'Sherlock' season 4 release date, spoilers news 2016: Benedict Cumberbatch hints 'end of an era' for detective series

Not much is being given away as far as "Sherlock" season 4's plot is concerned. However, talks are rife that the upcoming installment, which is slated for a January 2017 release, will be the last one for the series. Or at least, the last one with Benedict Cumberbatch in the titular role.

In earlier interviews, particularly during the San Diego Comic-Con in July, co-creators Steven Moffat and Mark Gatiss didn't give fans any firm assurances that season 5 will happen, but neither did they imply that the upcoming season will be the last one for the much-loved series. While Moffat said he will be "mildly surprised" if the series ends after season 4, they also said they're taking the series "one season at a time."

Currently, the series which airs on PBS in the US and BBC in the UK has not been renewed for season 5. This has only raised fears among fans that perhaps "Sherlock" season 4 will be the series' swan song. Both Moffat and Gatiss have declined to comment on the issue further, although they gamely shared that the upcoming installment will be the darkest one ever for the series.

Meanwhile, in an interview with Britsh GQ, 40-year-old Cumberbatch said that he felt season 4 is "like the end of an era" and that it was going "to a place where it will be pretty hard to follow on immediately."

"It feels like the end of an era, to be honest. It goes to a place where it will be pretty hard to follow on immediately. We never say never on the show. I'd love to revisit it, I'd love to keep revisiting it, I stand by that, but in the immediate future we all have things that we want to crack on with and we've made something very complete as it is, so I think we'll just wait and see. The idea of never playing him again is really galling."

He also said in an interview with Vanity Fair that he doesn't see himself returning to the character "for the immediate future."

Still, it looks like the actor will have his hands full even after "Sherlock" season 4 premieres in January since he will be working on three productions, including 2018's "Avengers: Infinity War," "Jungle Book," and "How the Grinch Stole Christmas."

As for the season 4 plot, it has been confirmed that Toby Jones will be playing the series' "creepiest villain" ever, Culverton Smith. There are even reports that Smith will cook up an evil scheme that might lead to the beloved detective's demise. Whether those speculations are true or not will be confirmed when the series returns on air.

"Sherlock" season 4 is set to premiere early January 2017.