A death certificate filed at a register office in London revealed that Ozzy Osbourne's cause of death was a heart attack.

The heavy metal rockstar died on July 22, weeks after he reunited with his Black Sabbath bandmates for the band's final performance.

Ozzy Osbourne, the heavy metal and reality television star, died of a heart attack and had suffered from coronary artery disease and Parkinson’s, according to a death certificate filed at a registry in London.