Ain't-it-Cool News CorrectionNews
The previously mentioned article from AICN has changed a wee bit. Quotage:
Timothy Spall has been cast as Peter Pettigrew for Harry Potter and the Prisoner of Azkaban. I made the mistake earlier of saying it was Professor Lupin he was playing ...
Although it's still a rumour at this point, it makes more sense, from a casting point of view (good call, B.K.!) :) (Thanks to Alan for the head's-up.)