Kelly Osbourne is mourning the death of her dad and rock legend Ozzy. On Thursday, the musician and daughter of the Black Sabbath frontman returned to social media for the first time, using the opening line to “Changes.” “I feel unhappy,” she wrote. “I am so sad. I lost the best friend I ever had.”

The Osbournes are reeling from the loss of their patriarch, and Kelly took to Instagram to memorialize Ozzy, honoring him with a very significant compliment.

The Osbournes” turned the heavy metal innovator into a reality TV star. Here are some moments that defined the show’s run.