'Sherlock' Season 4 Release Date: The trailer for the Sherlock season 4 holiday special 'The Abominable Bride' dropped and it shows Sherlock and Watson taking on a cold case in Merry OldeGotic England

The Sherlock season 4 Christmas special will air on Jan. 1, 2016. Sherlock season 4 will air later in 2016. The special episode will be available on the big screen. The theatrical version will have 20 more minutes of additional footage. Worldwide United Kingdom, in partnership with Hartswood Films, will offer viewers exclusive bonus material, including a guided tour of 221B Baker Street.

Rumors are circulating that this season may be the last. Show runner Steven Moffat told Variety that "Sherlock" will stop airing when Benedict Cumberbatch "gives up" the show.

"For example, once Benedict Cumberbatch gives up "Sherlock," what are we going to do? We are going to stop, that's what we are going to do," Moffat told Variety. "Most shows have a built-in mortality. But here is a show that sheds us all like scales; a show that can make you feel everything except indispensable. It will carry on forever, because you can replace every part of it."

Cumberbatch said will not be leaving the show anytime soon.

"If we can keep the quality up," Cumberbatch told Vogue. "I can't imagine that I will ever get tired of being Sherlock. I'd love to play him as an old man."

Cumberbatch recently told USA Today that he would play the detective as long as there's "room for character growth."

The "The Abominable Bride" trailer, which only runs 26 seconds, shows the "first meeting" of Sherlock Holmes, played by Benedict Cumberbatch, and Dr. John Watson, played by Fargo season 1's Martin Freeman. The pair are introduced by a mutual friend but Sherlock and Watson bond immediately over a tossed cane.

"Excellent reflexes. You'll do," Sherlock admires.

"The name is Sherlock Holmes and the address is 221b Baker Street," says the Sleuth.

"I'm an army doctor which means I can break every bone in your body while naming them," Watson tells Sherlock in another scene.

The special will also feature Mrs Hudson, played by Una Stubbs, and Watson's wife Mary Morstan, played by Martin Freeman's real-life partner Amanda Abbington.

Not much is known about the special besides that it will be set in gothic 19th century London. Although there are rumors that ghosts might be involved because they fit so well in a Victorian setting.

The Christian Post reported that co-creator Mark Gatiss said the special will be based on the Sherlock Holmes book "The Adventure Of The Musgrave Ritual."

"Sherlock" season 4 will finally air in early 2016.