"Now the band is both here and not here; with us, and yet gone," the Smashing Pumpkins frontman wrote on Instagram

Iommi also explained that the band only agreed to reunite for the Back to the Beginning concert because it would be a charity show. "It’s absolutely the end,” he said of Black Sabbath, which he formed in 1968 with Osbourne, Butler, and Ward. “There’s no way we could go out and do a tour.”

Even metal icons get the pre-show jitters, as Black Sabbath's Tony Iommi reveals ahead of tomorrow's historic final gig