The add-on, titled Minerva's Den, will see players taking on the role of a brand new character and teaming up with Brigid Tenebaum to fight a dictator's district in Rapture.
"Minerva's Den is a substantial addition that will give players more of what they're looking for: more story, more narrative, more gameplay and more of Rapture," said Christoph Hartmann, president of 2K. "The core team has created an exciting product that further enhances the mystery and allure of the world of Rapture. Minerva's Den will be a fitting conclusion to the BioShock 2 saga."
The add-on will take place in an entirely new district of Rapture, and will include new weapons, enemies and plasmids.
There's no word on pricing or dates yet, but we're reasonably excited by this announcement.