"Never say never." That's what Black Sabbath's Geezer Butler is saying about the prospect of more new music after '13' is released next Tuesday (June 11). Singer Ozzy Osbourne also says he'd like to cut more songs, but no one is making any promises.

"Let's put it this way," the singer tells Billboard, "It's taken us 35 years to do this one. "So if there's gonna be (another) album there's gonna be an album but I don't want to say if there's going to be a follow-up. I wouldn't mind doing another Sabbath album with them, though."

'13' is the first Black Sabbath album with Osbourne since 'Never Say Die' in 1978. It falls just short of being a full reunion album however, as drummer Bill Ward pulled out of the project after it was announced. Rage Against the Machine drummer Brad Wilk is replacing him for the album and upcoming tour dates.

Butler begins the Billboard interview by calling '13' their "final album," but backtracks. "Well, I guess you should never say never," he said. "It could be, though. We'll see how this album goes, see what happens."

Fans can listen to the entire album via a stream on iTunes right now. Look for the band to play three or four new songs during the North American leg of their tour, which begins July 25 in Houston, Texas. South American and European dates will follow.