The original Black Sabbath line-up of Ozzy Osbourne, Tony Iommi, Geezer Butler and Bill Ward are reuniting for a new tour and album.
But the news became official as the band made an announcement on their website at 11:11 am (Pacific Daylight Time) on November 11.
The band also directed fans and the media to the Whisky A Go Go nightclub in Los Angeles as speculation reached fever pitch on social networking sites.
The band are recording a new album with Rick Rubin and will tour the world in 2012.
They will headline the Download Festival at Donnington Park in June.
Black Sabbath released a youtube video called "Black Sabbath 11-11-11 announcement" with a secondary headline "REUNITED: 33 YEARS IN THE MAKING".
Black Sabbath made their Los Angeles debut at the club on November 11, 41 years ago.
In August, it was revealed that the band were planning to reform, with Ozzy Osbourne and Tony Iommi already having written new material.
“We’re really looking forward to it and I think the stuff we’ve been writing is really good,’’ 63-year-old Tony said.
“It’s more back to the old original stuff.’’
He added that the reunion has been kept under wraps for some time.
“Ozzy’s been the worst at trying to hold it back,” he said.
“He’s doing a lot of TV and he’s being asked stuff about a reunion and he’s going ‘well I never say never’. He told me, ‘I don’t know what to say’.’”
The band formed in Aston in 1968 and are considered one of the pioneers of heavy metal music. Their legacy was celebrated at a major exhibition in Birmingham over the summer, Home Of Metal.
Original frontman Ozzy, who later starred in his family reality TV show the Osbournes, was sacked from the band in 1979 because of his drug and alcohol addiction.
He was replaced by the late Ronnie James Dio.
Subsequent singers have included Deep Purple’s Ian Gillan and Glenn Hughes, Ray Gillen and Tony Martin.
The original line-up reunited in 1997 to headline the Ozzfest festival and released the live album, Reunion, recorded at Birmingham NEC in 1998.
The project came to an end when Ozzy resumed his solo career.
From 2006 until his death in 2010 Ronnie James Dio toured with Iommi and Butler under the band name Heaven & Hell.