From what Latino Review says, the "Mad Men" and "Resident Evil: Apocalypse" actor will play the arch enemy of Sherlock Holmes in the 2011 sequel of "Sherlock Holmes" (2009).
Jared Harris, is the son of actor Richard Harris and currently starring as Lane Pryce on AMC's MAD MEN.
The Main Villain of the Sherlock Holmes stories created by Arthur Conan Doyle was briefly saw in the first movie. But he was in the shadows, what would mean that any actor could play him in the sequels.
Harris joins Stephen Fry, Robert Downey Jr., Jude Law and Noomi Rapace on the cast of the sequel for Sherlock Holmes, that releases on the USA on 16 December 2011