Fans of BBC's 'Sherlock' are in for a treat as the show has finally been pegged with some concrete release dates for its upcoming Christmas special and highly anticipated Season 4.

The Christmas special will be the first taste of 'Sherlock' Season 4 that fans of the hit show are going to get, and its even timed appropriately, as it's set for a December 2015 release date.

Early reports claimed that there was a delay in the shooting of the fourth season, mainly due to its two main characters, Martin Freeman and Benedict Cumberbatch, who had conflicting schedules. The production team had to find dates to film which fit both the actor's calendars.

The filming for the Christmas special is going to happen in January of 2015. This means that the actual release of Season 4 will have to be long after the Christmas special. While this seems like a long time to wait, fans can read up on spoilers and what they can expect to see in the upcoming installment.

Before issuing the release date announcement, BBC One had been teasing about the comeback of the popular series. BBC One said it will be the most shocking one out of all the seasons. The broadcasting company also warned the viewers to be ready for unexpected surprises and new discoveries in the lives of the characters.

In terms of spoilers, Steven Moffat, creator of the show, revealed that the 221B Baker Street location will be used again. There is also some speculation that actress Amanda Abbington, who plays the character of Mary, will stick around for Season 4, which means that her character will not die, contrary to what the rumors are saying.