By Samantha Highfill
December 11, 2013 at 12:00 PM EST

Welcome, welcome … to the latest casting news for The Hunger Games: Mockingjay.

It was recently announced via Twitter that Prison Break‘s Robert Knepper will be joining both of the final films as Antonius. As exciting as it sounds, we’re not exactly sure what to expect, considering we’ve never heard the name Antonius before.

Regardless, check out the casting news below:

It’s official! Please welcome @Robert_Knepper as Antonius to the cast of @TheHungerGames: Mockingjay Parts 1&2.

— Catching Fire (@TheHungerGames) December 11, 2013

So who is Antonius? Stick with EW as we unravel the mystery.