Supernatural has been on the air for 14 seasons. 14. Seasons. That is basically forever in TV years! Now the CW series will celebrate its landmark 300th episode in the new year, so it's only natural that literally everyone in Canada (and maybe the United States) has appeared on the show at some point in time. Some of the actors have even left and returned years later. Case in point: The 300th episode will feature the return of Jeffrey Dean Morgan, who hasn't been seen since the end of Season 2, as Papa Winchester.

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All this got us thinking about how many people have actually appeared on the show over the years. For instance, did you remember that Battlestar Galactica's Tricia Helfer once appeared as a ghost? How about the fact Emmy winner Sterling K. Brown played a vampire in one of the show's early seasons? Seriously, the show is littered with familiar faces, so check out our comprehensive gallery of notable guest stars and the episodes in which they first appeared below. Some of the names may surprise, impress, and even confuse you.