Timothy Spall as Peter Pettigrew?
Casting rumors from Ain't it Cool:

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, so the TalkBackers below aren't crazy. At least, not more crazy than normal. As fans of the series know, Pettigrew is also called Wormtail, and Spall is a hell of a choice for him. If you’re not familiar with Spall’s work, shame on you. He’s one of those character actors who can go from hilarious to heartbreaking in one quick move, and right now, you can see him in Doug McGrath’s wafer-thin but enjoyable “Nicholas Nickleby”. He’s a welcome addition to the world of Potter, and should do a great job with Wormtail.

Copy & paste af <a href="http://www.mugglenet.com“>www.mugglenet.com</a><br><br><i>”There is no good and evil, there is only power, and those too weak to seek it.“</i>
<b>- Quirrel</b>

<i>”afhverju er Harry Potter fyrirmynd margra?… hann er lúði… sjáðu hann… meiri nördi en Shelob“</i>
<b>- RazhowR</b>

Það er komið <a href=”http://www.hugi.is/hp">Harry Potter</a> áhugamál! Takk fyrir vefstjóri! :D
She's well acquainted with the touch of the velvet hand, like a lizard on a windowpane