Speaking under conditions of strict anonymity to VG247 this morning, a source close to the matter has said that Rockstar North is working on a "brand new IP."
Cryptically, the spy added: "It's not 100 percent sure it'll ever see light of day, anyway."
The comments come after EGM published a rumour yesterday that the GTA developer is working on a new PS3 game, as well as putting together a third Max Payne.
Our source couldn't confirm whether or not the new IP was a PS3 exclusive.
Rockstar North is also working on DLC for GTA IV at the moment, the release date of which is still to be confirmed.