"The Adventures of Tintin: The Secret of the Unicorn", the Steven Spielberg directed and Kathleen Kennedy/Peter Jackson produced film, has hit theaters and has been a success. So, new of a sequel doesn't come as much of a surprise.  

The sequel is already in the works, and could be out  by late 2014 or early 2015. Peter Jackson has already signed on to direct the sequel.

Kathleen Kennedy recently told Collider, "It is being moved forward, in fact Steven and I were talking about it this morning. We're working on a script right now, we'll see a script probably February or March. If we can do some camera capture this summer, which I think we could do, then we would be on track to have the movie either Christmas 2014 or summer 2015, and so that's what we're looking at right now".