At the end of her July 22 Mayhem Ball performance in San Francisco, Gaga exposed an Ozzy Osbourne T-shirt underneath a black leather jacket, then played his 1980 debut solo single “Crazy Train” as she and her dancers walked a catwalk.

Gene Simmons paid tribute to the fellow rock icon. "Sad to report Ozzy has passed away. He was a giant. Admired and loved by millions of fans worldwide. Prayers and condolences go out to the Osborne family," the KISS rocker wrote, sharing a news link to his death.

Osbourne died Tuesday, just weeks after his farewell show. In 2020, he revealed he had Parkinson’s disease after suffering a fall.