These two were also commissioned by Warner Bros. to write a Sherlock Holmes sequel. In fact they began to write it before the first Sherlock Holmes was released. During their interview they even dropped a little update about the direction that the new film might be going in. Particularly they broached the subject of Brad Pitt playing Professor Moriarty in Sherlock Holmes 2. Here is what Michele Mulroney said:
Well, of course, we're gigantic Brad Pitt fans. I think he's a brilliant actor and a particularly brilliant character actor. And certainly the role that you're talking about of Professor Moriarty is a big character to bite off. I hope Brad likes it. Let's leave it at that. To be political, we should say nothing.
The writers went on to evade questions about the actual story but it seems like Pitt is, at the very least, someone who just might be playing the role in the film.