Black Sabbath brought their satanic rule to London's Hyde Park, turning the royal park into a giant mosh pit.
The British heavy metal band - frontman Ozzy Osbourne, guitarist Tony Iommi and bassist Geezer Butler - headlined the main stage at Barclaycard British Summer Time and had crowds headbanging as the sun went down.
The band treated fans to old favourites, including Iron Man as well as some tracks from their new album 13.
Ozzy told the crowd: "Do you know what day it is today? It's my f***ing wedding anniversary. Sharon! Get out here!"
But his wife and manager did not appear on stage.
The 65-year-old rocker confessed last year that he had fallen off the wagon during work on the band's latest album 13, but he overcame his battle with drink and drugs once again last year.
And Ozzy was on fine form, his powerful vocals a long way from the confused comedy character he was portrayed as on TV show The Osbournes, while Iommi, 66, mesmerised with his guitar skills.
The band opened with hit War Pigs, with images of war criminals including Osama Bin Laden and Hitler playing on the big screens behind the stage.
The show closed with classic Paranoid as the heavens opened and rain fell on the crowd, but nothing could dampen the hell-fire spirit of the night.