For as many questions as 'Sherlock' fans have over the eagerly anticipated third season, including those answered and glimpsed during the show's first panel at Comic-Con 2013, at least one major mystery has been thoroughly solved. Danish actor Lars Mikkelsen (yes, brother to 'Hannibal''s Mads) has joined the third cycle in the major villainous role, replacing Andrew Scott's "career criminal" Moriarty, but as whom?

Producer Sue Vertue first revealed the casting over Twitter, adding that Mikkelsen ('The Killing') will play the role of "Charles Augustus Magnussen," a character with no direct literary counterpart, but one that likely corresponds to 1904 Sir Arthur Conan Doyle story "The Adventure of Charles Augustus Milverton." There, Sherlock and Watson encountered the character as a murderous blackmailer.

Apart from the footage screened at Comic-Con 2013, we know of 'Sherlock' season 3 that there will be a definitive explanation of Sherlock's apparent return from the grave, and that Watson (Martin Freeman) will walk down the aisle with Sherlock (Benedict Cumberbatch) as his best man. Showrunner Steven Moffat previewed at Comic-Con that Andrew Scott would return to the role of Moriarty, though only as a corpse, given the idea of both characters having faked their respective suicides at the climax of season 2 finale "The Reichenbach Fall" would be "a waste of a scene."

You can check out the first photo of Lars Mikkelsen as Sherlock's new nemesis, Charles Augustus Magnussen, below, and give us your predictions for 'Sherlock' season 3 in the comments!

Sherlock Season 3 Lars Mikkelsen Charles Augustus Magnussen

More From ScreenCrush