The FX series, Justified, is gearing up to go into its fourth season at the beginning of 2013, and production has already kicked off on the gritty show about the corruption and lawlessness of rural life in coal-mining Eastern Kentucky.

It may come a couple of months early, but spoilers are already out in force, in light of an interview showrunner Graham Yost, 53, gave Tuesday night at the New York Television Festival, in which he revealed the upcoming storylines behind some of the anticipated Justified guest stars, including Patton Oswalt, who got a shot at playing Constable Bob after merely revealing that he was a fan of the show, reports Entertainment Weekly. "We just like the idea of this sort of cop wannabe, who's kind of a cop, interacting with [main character] Raylan [Givens, played by Timothy Olyphant] some."

And Oswalt isn't the only expected guest star. Yost hopes to invite Damon Harriman, who plays Dewey Crowe, to season four, of which he only has a few episodes penned thus far. "We love to have Damon come by once a season at least. We haven't actually landed on anything this year and we don't want to force it, but we'll see," Yost said, sticking to his trademark vagueness.

Jeremy Davies' Dickie Bennet also may have some surprises in store for fans, though Yost is also playing that one close to the vest. "We don't know what's gonna happen with Dickie, nor do we know what's gonna happen with Dickie's hair," he joked.

But Yost wasn't as vague about the past as he was the future. The writer opened up about his experiences drafting the hit 1994 movie, Speed, which starred Keanu Reeves, Sandra Bullock and Dennis Hopper. In retrospect, he largely credits Avengers and Buffy the Vampire Slayer writer and director, Joss Whedon, for saving his script. "Joss did a total dialogue rewrite on that script," said Yost, adding that Whedon is responsible for the line, "Pop quiz, hotshot."

Yost went on about his gratitude to Whedon. "When I read his draft, I went, 'Oh, thank god. Oh, he gets it.' He's a very funny writer, a very smart writer. So I was very, very lucky," Yost said.

Justified season four, also starring Nick Searcy, Joelle Carter, Jacob Pitts and Walton Goggins, returns to FX on January 13, 2013.

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