The unannounced game will be released for the PlayStation Vita, according to NeoGAF, although no launch date has been given.
Original story: An unannounced Uncharted game has been outed by the Australian age ratings board.
Uncharted: Fight for Fortune was given a 'G' (General Audience) rating, and will be released on multiple Sony platforms.
Little else is known about the title, other than the fact that it is being developed by One Loop Games.
One Loop Games has previously worked on Star Wars Episode III: Revenge of the Sith, Full Spectrum Warrior, and The Saboteur.
According to its official website, the studio has just completed its "first big game", which is said to be "unlike nothing you've ever seen before".
One Loop Games also has a second secret project in development, which it will announce soon.
Uncharted 3: Drake's Deception sold 3.8 million copies on the day of its release in November 2011.
A Game of the Year Edition, which added all previously released DLC, including map packs, character skins and game modes was released in September.
> Read Digital Spy's review of Uncharted 3: Drake's Deception
Watch a trailer for Uncharted 3 below: