Guy Ritchie's "Sherlock Holmes" won't open in theaters until Dec. 25, 2009, but Warner Bros. is already developing a sequel to the upcoming action adventure starring Robert Downey Jr. and Jude Law.

Launching sequels before the release of a film is the new thing in Hollywood, and I guess Warner strongly believes this one has franchise potential. Responses to footage shown at Comic-Con has been positive.

The Hollywood Reporter says Kieran and Michele Mulroney are set to start writing a draft for the follow-up. Also, Brad Pitt is in talks to join the sequel as Holmes' big enemy Moriarty. It was previously rumored he would show up in the first film.

In "Sherlock Holmes," Robert Downey Jr. stars as Holmes, while Jude Law is on board as Watson. Rachel McAdams plays his love interest, and Mark Strong will portray the villain. Check out a cool trailer here.

To tell you the truth, I'm quite excited about Ritchie's version of the classic detective tale. Let's hop it delivers the goods.