We've already heard that Mos Def and Colin Hanks would both join the sixth season of Showtime's acclaimed series Dexter, and now yet another fine actor has joined the guest star line-up. The cable network has revealed that Edward James Olmos, star of such films as Blade Runner, Stand and Deliver and the series remake of Battlestar Galactica, will return to TV for an extended character arc on the series. Olmos will play a brilliant, charismatic professor of religious studies, but it's not yet clear how he gets caught up in Dexter's exploits in the forthcoming season. Production begins on May 25th in Los Angeles, and season six is slated to premiere sometime this fall on Showtime. I'm sure there's plenty more guest stars to be revealed so stay tuned.