"Sherlock" is known for having long intervals between seasons. Hence, it has been a delight for the fans to know that a special episode of "Sherlock" is all set to air during the Christmas prior to season 4.

The last season of "Sherlock" also had a special episode during Christmas. However, this time, the episode will be different from the others as it will take back fans to the original era of Sherlock Holmes' creator Sir Arthur Conan Doyle's stories. Holmes will be a much nicer, decent person before he became the well-known cynical "sociopath".

In an interview with the Entertainment Weekly, "Sherlock" co-creator and co-writer Steven Moffat said that the reason they will release the special episode is that they wanted to showcase Sherlock Holmes and Dr. Watson in their original costumes for once.

"The episode will showcase Sherlock as a nicer person and a proper polished Victorian gentleman. He will not behave like a brat and like his usual sarcastic self," he said.

Benedict Cumberbatch, who plays the titular role, is reportedly happy with the idea. However, Cumberbatch also expressed concern that if it doesn't work well, fans will be disappointed.

Given that it will be just one episode, there should not be much to worry about it.

"Sherlock" season 4 is scheduled to start filming in early 2016 and will be released in 2017. The exact dates are yet to be announced.