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

Reuniting onstage for the first time in two decades, Black Sabbath performed to a sold-out crowd of 40,000 with its all-star, one-day-only charity festival Back to the Beginning, held in Ozzy Osbourne’s hometown of Birmingham on July 5 and serving as a farewell concert to and celebration of the longtime rocker.