'Sherlock' season 4 cast, spoilers: Sacha Dhawan boards series as new guest star

"Sherlock" season 4 may be introducing another new face.

Sacha Dhawan, who is best known for his roles in the film "The History Boys" (2006) and the drama series "In The Club," is joining the "Sherlock" cast as a guest star in its fourth season, Den of Geek has learned.

BBC has not confirmed the casting and production is being kept tightly under wraps, but CultBox has said that Dhawan's character will go by the name AJ.

According to the Radio Times, the actor's official CV on the Troika Talent website lists the "Sherlock" role of "AJ" among his television credits. While it has since been removed, the outlet has posted a screenshot of the CV, confirming the actor's casting.

In May, "Captain America: The Winter Soldier" actor Toby Jones was confirmed to have nabbed a role in "Sherlock" season 4. At the time, Deadline reported that the actor will be "bringing to life one of [Sir Arthur Conan] Doyle's finest villains."

According to Den of Geek, Jones will be playing the role of Culverton Smith, a tropical diseases "expert" from the Sir Arthur Conan Doyle short story "The Adventure of the Dying Detective."

In Doyle's work, Smith held a grudge against Sherlock (played in the series by Benedict Cumberbatch) after the latter suspected the former of murdering his nephew. It is unclear if this same storyline will unfold in "Sherlock" season 4.

As no changes to the BBC crime drama's main cast has been announced and/or rumored, it may be safe to assume that season 4 will find Cumberbatch, Martin Freeman, Amanda Abbington, Rupert Graves, Una Stubbs, Louise Brealey, and Jonathan Aris reprising their roles.

"Sherlock" creators Mark Gatiss and Steven Moffat issued a press release announcing the new season back in April.

"Sherlock [season] four — here we go again!" the creators said. "Whatever else we do, wherever we all go, all roads lead back to Baker Street — and it always feels like coming home. Ghosts of the past are rising in the lives of Sherlock Holmes and John Watson bringing adventure, romance and terror in their wake."

While the BBC has yet to announce the official release date for "Sherlock" season 4, fans expect the new season to debut in early 2017.