British actress Emma Thompson will play Professor Trelawney in the third Harry Potter film, Prisoner of Azkaban, ending rumours about the role.
Director Alfonso Cuaron said: "I am very excited to work with Emma. She brings such life and spirit to the characters she portrays."
There are reports that Azkaban will be a lot darker than the other films.
And, excitingly, pre-production has already started on fourth film, Goblet of Fire.