I don't want to insult your intelligence because we both knew that Warner Bros. was already working on a sequel to "Sherlock Holmes" even though the film doesn't come out for another three months.  That's how Hollywood works with its franchises now.  You don't want to get caught flat-footed, have your leading talent unsigned, and let the opportunity for money slip away.  It's a low-risk, high-reward play because even if the first film doesn't succeed, you can just throw it back into development hell and move on to something else.  So news of a planned sequel isn't what's supposed to spark your interest.

What's supposed to spark your interest is that Brad Pitt may play Holmes' primary antagonist, Professor James Moriarty.  You probably want to hit the jump for more on that.

According to THR's Risky Biz Blog, Pitt has had discussions with the producers to play Moriarty but there's not a firm deal in place.  Granted, Pitt has worked with "Holmes" director Guy Ritchie in the past but it's obviously difficult to lock down Pitt due to his high demand.  However, there are rumors (and I believe them) that he's in some shots for "Holmes" but the script says he stays in the shadows.  I'm wondering if the truth lies somewhere in the middle with Pitt providing an off-screen voice for Moriarty.  It would also seem like the safest bet just in case Pitt can't return for the sequel.  However, if Pitt does get cast as Moriarty, then the only leading cast member who's actually British would be Jude Law (the first film also has the born-in-the-UK Mark Strong as the antagonist, Lord Blackwood).

It's clear that Warner Bros. has high hopes for the franchise and should "Holmes" and the upcoming "Cowboys vs. Aliens" both prove successful, then along with "Iron Man", Robert Downey Jr. will have three franchises and will confirm my suspicion that he's been cloned; that there are multiple Downeys running around giving great performances in at least a half-dozen films every year.