Although filming for "Sherlock" Season 4 has not even begun yet, fans of the highly anticipated TV show were gifted with a fan convention scheduled in the second quarter of this year, says iSchoolGuide. The three-day event will be held at the Excel Center in London from April 24 to 26, 2015.

Another surprise is that "Sherlock" fans will finally have their first official sneak peek into the show's standalone Christmas special, which will be shown on Dec. 25 this year. Flickering Myth leaked some of the on-set photos on the Internet.

This episode will not be part of the show's fourth season, and will also be released before the upcoming season even starts. This Victorian-themed Christmas special reunites Martin Freeman as Dr. John Watson, Benedict Cumberbatch as Sherlock Holmes, and other significant characters of the show who fans already know, says Christian Today.

Moreover, Design & Trend says that Mark Gatiss, the co-creator and writer of the show, may have provided his fans and followers a few hints about the Christmas episode's plot. Apart from his production work behind the scenes, he also stars in the much awaited BBC series as Sherlock's older brother, Mycroft Holmes.

Gatiss posted a photograph on Twitter that showed a store sign that read, "Jabez Wilson, Pawnbroker, Est. 1854," with what looked like a blue vase behind the glass. "We Gingers must stick together #Sherlock," he wrote as a caption.

Although his social media post was cryptic, it was enough to send "Sherlock" fans into a frenzy, spewing their own share of speculations about the upcoming storyline. Many immediately speculated that the episode will be based on "The Adventure of the Red-Headed League," which comes from Sir Arthur Conan Doyle's collection.

"We're ready to unleash the most shocking and surprising series of #Sherlock yet," BBC One revealed, according to News Everyday. "The only thing to expect is the unexpected."

In a set of "Sherlock" photos that Daily Mail posted, Natasha O'Keeffe is seen standing on a balcony wearing what looked to be a Victorian-themed bridal gown. She also had two vintage silver pistols in her hands. The images then reveal that she points one of the guns into her mouth and fires as blood and brain parts are splattered behind her. Whoever O'Keeffe is going to portray will not be staying in the show for long.

"A special, plus a new series of three episodes - it's a record-breaking run!" says Steven Moffat, co-creator, writer, and Executive Producer. "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."