Despite trying to keep the bag closed, the cat been roaming around for a while now, and even if it was revealed in a recent issue of Famitsu. The game hasn’t been officially announced yet by Tecmo, that was until GDC.

When standing in front of a area filled with game journalists, director Yosuke Hayashi officially announced that Tecmo is busy working on the PS3 version of Ninja Gaiden II, Ninja Gaiden Sigma 2.

Sigma 2 will feature online co-op play, with Ryu being able to team up with either of his female companions - Ayane from Dead or Alive, and Momiji from Ninja Gaiden Dragon Sword. However, Hayashi explained that online play would not feature player-versus-player combat.

He also revealed that all the extra content in Sigma wouldn’t be made available for the 360, but he admitted that Team Ninja was also considereng downloadable content for the game on the PS3.

[Tecmo announces Ninja Gaiden Sigma 2 for PS3 (officially) via ArsTechnica]