Dexter - Interview with Colin Hanks

How did you get the part?
It came through quasi-normal channels. The only thing that was sort of unusual was I got a phone call saying, “Hey, they want you; they wanna offer you this role,” which doesn’t happen very often. And so I had a phone conversation with [producers] Scott Buck and Sara Colleton. They told me a little bit about the character and said, “I hope you’d consider doing it.” And the whole time, I’m sitting there like, “I don’t really have to consider.” So normal channels, but different than any other sort of job that I’ve ever done before.

What was your reaction to the story line when they explained it to you?
Well, when they told it to me, it was incredibly vague. They just said, "You’ll be one of the two bad guys; you’ll work together as a team." And then they said — well, I can’t really say because we haven’t aired yet — but they told me a version of what is going to happen at the end, which was sort of like the caveat. Which ended up not happening, by the way.

The end changed from when you got the role?
Yeah, as with all things TV, it’s always fluid, it’s always morphing, it’s always changing, it’s always growing. And I think there was a lot of that throughout the course of the season. They didn’t tell me about the twist in — I think it was the “Get Gellar” episode — until right before they sent that episode out.

Source: Full interview @ Vulture