Tool is one of the many bands on the bill for "Back to the Beginning" — the big, all-day event that will end with Black Sabbath and Ozzy Osbourne's final performances — but the band initially declined the offer.

Guitarist Adam Jones explained what happened in a new interview with Guitar World, recalling how he and his bandmates reacted when Tom Morello, who's the event's musical director, first contacted them. “The four of us were on the phone, or texting – I can’t remember – and someone went, ‘I don’t think I can do it.’ Someone else went, ‘Okay, yeah, I think I’m gonna do this other thing,’... I think I even went, ‘Yeah, let’s not do it.’ But it was really an honor that they asked us," Jones said.

A few months later, Morello contacted Jones directly and asked if he'd be interested in performing a song with him and Smashing Pumpkins' Billy Corgan. After agreeing, Jones learned that his bandmates Danny Carey and Maynard James Keenan were also performing with other acts.

“I went, ‘I didn’t know that.’ It hit me, and I said, ‘If the three of us are there – and I know Justin [Chancellor] will want to do it.’ I went back to our people and went, ‘Why don’t we just do it? We’re all going to be there," Jones recalled. "That’s how it happened – and why it was announced later."

Metallica, Guns N' Roses, Slayer, Pantera, Gojira, Halestorm, Alice in Chains, Lamb of God, Mastodon, Anthrax and Rival Sons will also be performing at the event, which is set to go down July 5 at Villa Park in Birmingham, England.

The BOB & TOM Show