'Sherlock' to Return With Special Before Fourth Season

New Blood

In addition to welcoming Mary Morstam (Amanda Abbington) into the fold, Sherlock also will introduce Sherlock's nemesis Charles Augustus Magnussen (Lars Mikkelson).

Sherlock is back — in bits and pieces.

The hit BBC One series, which stars Benedict Cumberbatch and Martin Freeman and airs stateside on PBS Masterpiece, will return for a special, followed by a fourth season of three new episodes.

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"A special, plus a new series of three episodes — it's a record-breaking run! Of course, it's far too early to say what's coming, but we're reasonably confident that the very next thing to happen to Sherlock and John, is the very last thing you'd expect," co-creator, writer and executive producer Steven Moffat said in a statement.

Fellow co-creator, writer and executive producer Mark Gatiss added, "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!"

Shooting on the Sherlock one-off special will begin in January 2015, with the series shooting later next year, the network announced on Wednesday via a creative Twitter campaign.

The announcement was initially teased on Tuesday (U.S. time) with cryptic tweets from the network's handle, including a GIF of the final scene of season three, which hinted at the return of none other than Sherlock's nemesis, Jim Moriarty (Andrew Scott):

Additionally, the @BBCOne Twitter profile page was taken over by Moriarty, as featured in the avatar and the username: "Sherlock - #221back."

Season three wrapped with Moriarty's "Did you miss me?" message being broadcast on every screen in London, causing Mycroft Holmes (Gatiss) to overturn Sherlock's exile assignment. The cliff-hanging image from Moriarty was particularly haunting, as Moriarty had shot himself in the head back in season two, and was only featured in a short scene (in captivity, and set deep in Sherlock's mind) in the season-three finale.

American fans awoke to the final announcement, once again via Moriarty's voice:

Immediately after the announcement was made, the profile's avatar was changed back to the BBC One logo, adorned with the detective's signature hat.

Sue Vertue, executive producer, Hartswood Films, also said in the statement, "It's taken a little while to get the dates sorted as none of the boys are exactly sitting back twiddling their thumbs, but there was unanimous goodwill to make this work, so we're thrilled that 221b is going to be inhabited again."

The news of a special comes just days after Freeman told to The Daily Telegraph, "If that's going to be a special — I'm speaking off-message here; if this was New Labour I'd get fired — I think that might be for next Christmas. A Christmas special. That's what I understand." Yet while Watson's wife, Mary (Amanda Abbington), is also set to return, Freeman continued, "While we play fast and loose with the original stories, we generally follow the trajectory of what [Sir Arthur] Conan Doyle did. So he [Watson] gets married, and then Mary dies — so at some point presumably she'll die."

Freeman let the notion of a special slip in another interview in April, telling Alan Carr of Chatty Man, "Mark Gatiss may beat me up, but there is an idea for this one-off special that's such a good idea, and as I was listening to it, I thought, 'We've just got to do this.' And I don't know when we are going to be able to do it, unfortunately. It's a fantastic, really mouth-watering idea. But I really don't know when we are going to get to do it."

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Co-creator Moffat, who also serves as showrunner for sci-fi evergreen Doctor Who, and Gatiss previously confirmed that a fourth series is on its way. "It will continue until Benedict gets too famous," Moffat said at a TCA panel in January, half-joking, with Cumberbatch adding, "I'm going to keep going with it. ... It's a schedule-providing thing. ... I love it. I find it very invigorating."

And when asked at a panel in March if they see the show continuing long into the future, Gatiss said, "The idea of growing older with it would be great. But it is hard to get everyone back together, because they have become extremely famous — except for us."

Sherlock is written and created by Moffat and Gatiss, and inspired by the works of Sir Arthur Conan Doyle. Sherlock is produced by Sue Vertue and the executive producers are Beryl Vertue, Gatiss and Moffat for Hartswood Films, Bethan Jones for BBC Cymru Wales and Rebecca Eaton for Masterpiece.

Email: Ashley.Lee@THR.com
Twitter: @cashleelee