My bad, they only confirmed it. Close enough though. They're probably aiming to release it like JUST before the GF100.
http://www.brightsideofnews.com/news/2010/3/3/sapphire-ready-to-launch-radeon-hd-5990-4gb.aspx
http://www.brightsideofnews.com/news/2010/3/3/sapphire-ready-to-launch-radeon-hd-5990-4gb.aspx