http://www.fandompost.com/2015/11/17/jojos-bizarre-adventure-part-4-diamond-is-unbreakable-anime-staff-cast-announced/
the show will be directed by Naokatsu Tsuda, returning from Stardust Crusaders, with Toshiyuki Kato serving as the series director and Yuuta Takamura as the chief episode director. They’ll be working off of series composition by Yasuko Kobayashi and character designs by Terumi Nishii
The cast includes Yuuki Ono as Jousuke Higashikata, Yuuki Kaji as Kouichi Hirose, Wataru Takagi as Okuyasu Nijimura, Takahiro Sakurai as Rohan Kishibe and Daisuke Ono as Joutarou Kuujou