UPDATE: Sony has now updated the official US PlayStation blog to confirm God of War: Ascension's existence.
The game director is Todd Pappy, who was design director on God of War 3 at Sony Santa Monica studio. Sony described Ascension as "the most ambitious God of War adventure in the series so far", and confirmed it as a prequel. It "takes us right back to where it all began", Sony said. "Discover the origins of Kratos as he takes his first steps on a now legendary quest for freedom."
ORIGINAL STORY: God of War: Ascension has been leaked by online mega-shop Amazon, who has also provided an initial teaser trailer and box art for the game.
Ascension appears to be the final name for the long-rumoured God of War 4 - a PlayStation 3 exclusive.
The teaser trailer depicts the return of series hero Kratos. Narration hints that the game will concern events before Kratos became the Ghost of Sparta, suggesting Ascension will be a series prequel.
"Join Kratos as he seeks freedom, redemption, and the clarity to avenge his family in the most ambitious God of War adventure in the series so far," read Amazon's product description.
The trailer and box art lie below.