Good news for Sherlock fans as the Sherlock season 4 release date could probably be moved to 2015 if the production goes along without a hitch, if the reports and rumors are to be believed.

Comic Central City has reported that filming for the season 4 of Sherlock has started and if all goes well, BBC is considering the possibility of airing new episodes this 2015, aside from the confirmed Christmas episode that would air this December.

Martin Freeman and Benedict Cumberbatch were seen filming at the Coston Hall in Bristol, England and Coston Hall is where the Sherlock Season 4 Christmas special episode is being shot.

In an interview with the Independent, Martin Freeman has admitted that the filming schedule for Sherlock allows him and Benedict Cumberbatch to keep things fresh.

"It's so intermittent. That's what for me makes it doable ... I don't know about [Benedict Cumberbatch], but certainly for me it would soon lose a lot of its appeal if we were schlepping that around for eight months of the year, every year. A bit of the sheen would have gone off it," Freeman told The Independent.

Meanwhile, Kpopstarz reported that speculation for the new series focuses on Sherlock and Molly's friendship, which viewers are hoping will evolve in season 4.

It has also been reported that Tom Hiddleston will play the third Holmes Brother, Sherrinford. It should be noted that Sherrinford was not featured in the stories of Sir Arthur Conan Doyle, but fans are sure that he will appear in the series.

Speaking to BBC TV, Cumberbatch recently said he has no plans to quit Sherlock now that his star is rising in film.

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