Tony Iommi, Black Sabbath guitarist and co-founder, told UK broadcaster ITV that Osbourne was “frustrated” during the band’s farewell concert on July 5. The heavy metal icon died less than three weeks later, on July 22, at age 76.

Osbourne died on Tuesday at 76, just weeks after he and Black Sabbath performed at their farewell Back to the Beginning concert earlier in July.

Ozzy Osbourne has died at age 76 more than two weeks after his final performance. The “Prince of Darkness” died “surrounded by love” on Tuesday, July 22, according to a statement posted by Osbourne’s family on social media.