'Justified': Adam Arkin guest-starring as Theo Tonin
Arkin has directed five episodes of "Justified," including the Season 1 finale. He'll be appearing in episode 311 and the Season 3 finale.
Executive producer Graham Yost tells EW that viewers will get more back story on Quarles and Theo in episode 310.
"Theo saved his life, but in a weird way," Yost says.
He also adds that Arkin will have a unique look for his "Justified" acting debut.
"I don't want to give it away. There is a physical tweak that Adam asked for," he says. "Adam wanted to be distinctive, so when you see it, it's like, Oh wow, that's pretty wild. He's not dressed as a pirate or anything. But he looks cool."
We wonder if the physical tweak has anything to do with aging Arkin up a bit. Theo Tonin's son Sammy just arrived in Harlan and is played by Max Perlich, who is not that much younger than Arkin.
"Justified" airs Tuesday nights at 10 p.m. ET/PT on FX.