This is unusual for Mark Sheppard.

The actor, who returns to Leverage this Sunday in the key role of Jim Sterling, often calls the Screen Actor's Guild and receives special permission to NOT have his name included in the opening credits. It's all in the name of surprising the audience and telling the best story, Sheppard said to me on the phone today.

But the word is officially out, so what can the popular, extremely busy actor tell fans about his role on "The Queen's Gambit Job?"

Sterling faces a "time crunch issue," Sheppard says. "Something needs to be done in a short space of time. There are no legal means by which to do it, so who are you gonna turn to?"

We all know the answer to that question, of course, but we won't know a lot more about where things go until we tune in on Sunday. Sheppard wouldn't say much about the cliffhanger or whether he'll return to Leverage this fall.

The actor does enjoy the dynamic between his character and Timothy Hutton's Nate, however. He jokes that Sterling is "kind of like Nate's ex-wife" because "the further we go with them, the more we learn about their past."

Going back a few years, meanwhile, Sheppard said he was shocked to hear that he didn't have to audition for this role and that it was originally in the script as "The Mark Shepperd." He had never even met Leverage creator Dean Devlin, but the pair shook hands and Devin simply asked: "So, do you wanna play him English or Irish?"

Leverage concludes its summer season on Sunday and then returns on November 27.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.