Kelly Osbourne is grieving the loss of her father Ozzy Osbourne.

Following the Black Sabbath frontman’s death on July 22 at age 76, his daughter shared a touching tribute on her Instagram Story July 24 with lyrics to his 1972 song “Changes.”

“I feel unhappy,” the 40-year-old wrote. “I am so sad. I lost the best friend I ever had.”

Just days before Ozzy’s passing, Kelly—who costarred on the MTV reality series The Osbournes with her dad as well as mom Sharon Osbourne, 72, and brother Jack Osbourne, 39, from 2002 to 2005—addressed online speculation that the heavy metal icon’s health was deteriorating.

“There’s this video going around on social media and it’s supposed to be my dad, but it’s AI,” she said in a clip posted on her Instagram Stories July 11. “It has a voice like my dad’s David Attenborough or something, and it starts out saying, ‘I don’t need a doctor to tell me that I’m going to die. I know I’m going to die.’”

Kelly went on to condemn the creators of the viral video before plainly stating that her father was “not dying.”