Robert Knepper may be all set to play classic DC Comics villain Clock King on this week's episode of "Arrow," but when it comes to "The Hunger Games" he's as in the dark as we are.

On December 12, 2013 it was announced the actor would be playing Antonius in "The Hunger Games: Mockingjay -- Part 1" and "Part 2." Only problem, Antonius is a character that doesn't exist in the book... And for a series that has been extremely faithful to its written progenitor, this is a development that sent fans into a frenzy.

So when we hopped on the phone with Knepper to talk about "Arrow," we had to sneak in a question about the mysterious role.

"I don't even know yet!" Knepper said laughing. "I know what I read for. I read, this was last summer... This is a huge movie. This is a huge two movies, and I know that what I got is not what I'll end up doing, they're so secretive about this."

For roles in blockbusters like "Hunger Games," this is pretty typical: an actor will audition for a role reading "sides," short pieces of script that give the sense of the character while not actually being from the movie's script itself. This is done not just to prevent leaks and spoilers, but also because a character as they appear in the movie may have minimal dialogue that doesn't suggest everything a casting director needs to see in an audition.

Knepper did get the part, though, and will be heading to Paris in April to shoot his segment of the mega-franchise. Hopefully by then he'll have a better idea of what to expect.

"You're going to find out when I find out," Knepper continued. "Well, I'll find out a little bit sooner than you, but I still haven't found out for sure!"

You can catch Knepper tonight at 8 p.m. ET on The CW in "Arrow," which we'll have a more in depth chat about here on MTV News later today. "The Hunger Games: Mockingjay -- Part 1" hits theaters on November 21.