The fourth series of the Benedict Cumberbatch and Martin Freeman drama is back on New Year's Day. We bring you everything you need to know about its return.

Sherlock series 4: Everything you need to know about the return of the BBC One Benedict Cumberbatch drama

Sherlock is undoubtedly one of the biggest shows on TV.

Drawing more than 8 million viewers on New Year’s Day this year, anticipation for the fourth (and potentially final) series of the hit BBC One drama is already growing.

There is now a trailer to whet your appetite further. Below, we bring you everything you need to know about the next series of the Benedict Cumberbatch and Martin Freeman drama.

When is Sherlock going to be on TV?

The BBC have confirmed that series four of Sherlock will begin on January 1, 2017.

There will be three episodes in the fourth series. One will be written by Steven Moffat, another by Mark Gatiss and the third a collaboration between the two of them.

Who is in Sherlock series 4?

Benedict Cumberbatch will be back as Sherlock, with Martin Freeman as John Watson.

Amanda Abbington (Martin Freeman’s partner in real life) will also be back as Mary Morstan, with John and Mary set to become parents for the first time.

Regulars DI Greg Lestrade, played by Rupert Graves, and Louise Brealey as Molly Hooper are both also returning.

Meanwhile, Toby Jones has been cast as a villain – although further details of his character are being kept under wraps. Speculation has him down as Culverton Smith, from Arthur Conan Doyle’s story The Dying Detective.

Sherlock also seems to have found himself a hound…

"He was very sweet", says Cumberbatch of his canine friend, "but was a bit afraid of being in the centre of town, afraid of too many people and not great on hard surfaces. We were in Borough Market, with lots of people around, on concrete and tarmac.

"Cut to Amanda literally pulling a bloodhound around London who was supposed to pull her around London. That was fun!"

Will this be the last series of Sherlock?

Possibly. In a recent interview, Steven Moffat said: “I don't know how long we can keep it going. I'm personally willing, but I'm hardly the main draw.”

He added: “I would be moderately surprised if this was the last time we ever made this show – but it absolutely could be."

The sheer success of Sherlock could prove to be its undoing. Since launching Benedict Cumberbatch and Martin Freeman’s careers into the stratosphere and firmly on to the international stage, the pair is more in demand than ever before.

With tricky schedules to negotiate as the leading men become even bigger stars, fitting Sherlock’s filming into their diaries could become more of an issue as the series continues.

However, in a recent interview Benedict was adamant that his new role as superhero Doctor Strange in Marvel’s new film of the same name will not impact on his future in Sherlock.

What else do we know?

It looks like this series could be the darkest yet for the super-sleuth and his medical sidekick.



"Sherlock goes through a massive emotional ringer this year, they all do for various reasons which I can’t explain," says Gatiss.

"It’s a cliché to say it’s the darkest season, but it is. It’s the darkest, but also the most meaty, with the most proper dramatic incident we could possibly throw at them all."

There are unconfirmed rumours that Tom Hiddleston might appear in the upcoming series after he was photographed at a convention alongside Mark Gatiss and Amanda Abbington, sparking speculation that he could be playing a sibling of Sherlock and Mycroft.

One earlier trailer briefly featured Moriarty – and no matter how many times he’s confirmed as being dead, rumours about Andrew Scott’s return to the show fail to cease.

The teaser also states that “everything they know will be tested” and that “everyone they know is under threat”.

Photo credits: BBC / REX