There's no news yet on key roles like Sirius Black or Professor Lupin.
But we can tell you that the role of Aunt Marge - Uncle Vernon's monstrous sister - will be played by British actress Pam Ferris.
Some of you may remember her from series like The Darling Buds of May and Where the Heart Is.
Filming on Azkaban is due to start in the first few months of next year.
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