Benedict Cumberbatch and Martin Freeman will be returning to 221B Baker Street next year as Sherlock and Watson. The series' creators, Steven Moffat and Mark Gatiss, have confirmed the series will return for a special in 2015 followed by three episodes. But we're in for a long wait...

Benedict Cumberbatch and Martin Freeman
Benedict Cumberbatch and Martin Freeman star in Sherlock.

The special and the three episode fourth series will begin filming in January 2015 and will air later that year. Freeman has let slip that he suspects the series will be aired at Christmas time, as the previous two series have been. Speaking to the Telegraph, Freeman said "I think that might be for next Christmas. A Christmas special. That's what I understand."

As we saw in the last episode of the third season, Holmes was nearly exiled but was saved (in a way) by the reappearance of his nemesis Moriarty. The series continues to be a catalogue of twists and turns which delight and shock audiences. Yet, according to the show's creators, season four promises to be "the most shocking and surprising series of Sherlock yet."

Read More: Benedict Cumberbatch Reveals He Was Close To Turning Down Sherlock Role.

Creator Moffat, speaking to the BBC, said he and co-writer Gatiss are aware of the direction they want Sherlock to go in although they are in the early stages of writing. He said "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."

The cast of Sherlock is "terrifically excited" for season 4 of the hit BBC show.

It appears Cumberbatch and Freeman's busy schedules are the reason behind the delay in production. The show has contributed to their rise and popularity. Freeman has recently appeared on UK and US screens in Fargo, the hit FX series. He will also be obliged to publicise the upcoming instalment in The Hobbit Trilogy, due to be released in December. Cumberbatch's diary is also fairly full, the actor finished filming The Lost City of Z earlier this year and is due to film Black Mass, opposite Johnny Depp, and as codebreaker Alan Turing in The Imitation Game

However, the cast and crew have been determined to ensure Sherlock continues. Sue Vertue, from the company who makes Sherlock Hartswood Films, said "there was unanimous goodwill to make this work so we're thrilled that 221b is going to be inhabited again." Gatiss also said the entire crew were "terrifically excited" to work on the fourth season.

Read More: If Benedict Cumberbatch Dies, Sherlock Dies, Says Mark Gatiss.

Sherlock season 4 probably will not air until Christmas 2015.