Kelly Osbourne is speaking out for the first time publicly about her father Ozzy Osbourne‘s death … and she’s using some Black Sabbath lyrics to express herself.

Ozzy’s daughter just posted on social media for the first time since he died Tuesday and she’s quoting the Black Sabbath song “Changes.”

Kelly’s post reads … “I feel unhappy I am so sad. I’ve lost the best friend I ever had.” She includes a broken heart emoji.

The song is a piano ballad from Black Sabbath’s 1972 album “Vol. 4” and it was originally inspired by drummer Bill Ward‘s split from his first wife.

Kelly covered the song with Ozzy in 2003 and it became her first No. 1 single in the United Kingdom. She also performed the ballad live with her dad onstage for years.

As you know … Ozzy died Tuesday and took his last breath with his wife, Sharon, and his kids — including Kelly — by his side.