I didn't see it, but I know he's been contracted to play a villain in the new season. There's a thread on it
here It does contain specific spoilers, so beware if you don't want to know too much.
I've changed the title of your post, cookiesmom, to something less of a spoiler - just in case there are those who don't want to know in advance that Dean appears or what part he plays.
LabRat