Metallica will top the bill on Saturday (9), while Sabbath headlines the Sunday (10) showcase.
A third headliner - for opening day on Friday (8) - has yet to be announced, along with the dozens of acts that will fill out the weekend.
Sabbath’s return to the stage follows last week’s reunion announcement that the band will not only do a world tour, but record a new album, as well. Rick Rubin will produce the first Sab studio effort since 1978’s "Never Say Die".
Metallica will rock Download with a full performance of their self-titled 1991 "Black" album, saying, "the dudes who run it asked us how we felt about playing 'The Black Album' in its entirety and we thought 'hold on, that could be really cool since it is technically the tail-end of the 20th anniversary of the release (August '91)'. So come hang with us for the 2012 version of our European Summer Vacation featuring 'The Black Album', with the exclusive stop in the UK on June 9."