'Sherlock' season 4 spoilers: Mysterious new character revealed

"In The Club" star Sacha Dhawan is joining Benedict Cumberbatch and Martin Freeman in "Sherlock" season 4, although his role is still being kept a secret.
His casting in the series is yet to be officially announced, but his online curriculum vitae (CV) precipitately revealed he will be on the show to play a character named AJ.
The actor confirmed the casting by retweeting posts about his "Sherlock" season 4 gig. There's no information if his character will be a friend or a foe to Sherlock.
Dawan has already worked with "Sherlock" co-creator and executive producer Mark Gatiss. The "Mr. Selfridge" star played "Doctor Who" original director Waris Hussein in a production about the origin of the science fiction series.
Prior to Dawan's casting, "Captain America: Winter Soldier" actor, Toby Jones was announced to play the role of a villain for episode 2 of "Sherlock" season 4.
The actor's online CV also gave away his role on the show. He will play Culverton Smith, a character from Sir Arthur Conan Doyle's 1913 story "The Adventure of the Dying Detective."
Spoiler Alert! The following contains potential spoilers for "Sherlock" season 4. Proceed only those who want to know.
In the story, Culverton attempts to kill Sherlock with an infectious disease after volunteering to cure an illness the detective feigned to apprehend Culverton for killing his own nephew.
According to rumors, "Sherlock" season 4 will also mark the return of Sherlock's nemesis James Moriarty (Andrew Scott) and the introduction of the third Holmes brother.
The description for "Sherlock" season 4 reads:
Ghosts of the past are rising in the lives of Sherlock Holmes and John Watson bringing adventure, romance and terror in their wake. This is the story we've been telling from the beginning. A story about to reach its climax...
"Sherlock" season 4 is expected to premiere early 2017.