Star Ocean developer tri-Ace helped make Final Fantasy 13-2.
The Japanese role-playing specialists helped Square Enix with game design, artwork, programming and other areas, tri-Ace producer Yichiro Kitao revealed on Twitter (translated by Andriasang).
tri-Ace is the studio behind Infinite Undiscovery (2008), Star Ocean: The Last Hope (2009) and Resonance of Fate (2010) - and has a long-standing relationship with Square Enix, publisher of a number of its games.
tri-Ace staff members appear in the Final Fantasy 13-2 credits. The sequel is out now in Japan. It launches in Europe in February 2012.