Ozzy Osbourne is hailing the forthcoming Black Sabbath reunion project as a return to form for the band, which hadn't produced a studio effort with him since 1978. "The album is mindblowing, (that's) how good it is," Osbourne tells Australian radio station Triple M, via Blabbermouth. "I'm so over the moon about the way the album turned out."

Osbourne admits that their late-1970s studio finale, the tepid 'Never Say Die,' was a letdown -- and he was determined to improve upon it: "People have been quoting me that this album was quite possibly the most important album of my career," Osbourne added. "What I meant by that is I didn't want it to sound like a follow-up to 'Never Say Die!,' 'cause that was when we were dying out within the band."

Rick Rubin produced the forthcoming '13,' the first in 35 years to feature Osbourne, guitarist Tony Iommi and bassist Geezer Butler. Original drummer Bill Ward has been replaced by Brad Wilk of Rage Against the Machine, after contract negotiations broke down. The album, which includes a trio of epic songs that clock in at more than seven minutes a piece, is due on June 11 via Vertigo-Universal Republic. A long-awaited tour will follow.

"Rick Rubin, I'd run into him from time to time over the years, and he goes, 'Any chance of Sabbath reforming, if you do, I would love to produce the album,'" Osbourne said. "And he did such a great job on the album. I know if you're a Sabbath fan, you will not be disappointed. It's so Sabbath-y, it's scary. It's the album we should have made after (1973's) 'Sabbath Bloody Sabbath.'"