Black Sabbath wrote all the lyrics to '13' the night before they were recorded.

Bassist and lyricist Geezer Butler was under pressure to come up with the ideas for the band's latest album - their first with vocalist Ozzy Osbourne in 33 years - and while he found it harder than in the band's 70s heyday, he didn't mind too much because he works better that way.

He told website ''It used to come naturally back then. Plus they would be written while we were doing gigs, over a period of time. Whereas this album I literally had to write the lyrics the night before Ozzy sang them, so I didn't have any time.

''Literally the night before. I think there was one song, 'Dear Father', which I'd written about 12 months ago. But when push comes to shove, it had to be done. And I work better under pressure.

''It's just trying to come up with different themes for the songs, that's the hardest part. Once I worked out what I was writing about, it made it a lot easier.''

Ozzy - who went on to have a successful solo career after leaving the band in 1978 - also contributed some lyrics of his own.

Geezer added: ''Although I did most of the lyrics, Ozzy did four sets of them, I think. Originally we did 16 songs, but there's [only eight on the album]. Ozzy did four, and I did 12.''

Geezer - who makes up the band with Ozzy and Tony Iommi - also said he can't wait to get out and play live, after months of rehearsals and recording.

He added: ''As a musician the best is being onstage, in front of a crowd, because that's when you give the most. And you get the most back.

''The worst is when you're in rehearsals; you're just playing to a wall.''

Black Sabbath's '13' is released on June 11, but fans can stream the album exclusively on iTunes for free at