Osbourne was fired from Black Sabbath in 1979 due to alcohol and drug problems, but went on to have a successful solo career, releasing 12 studio albums, the first seven of which received multi-platinum certifications in the US. Osbourne has since reunited with Black Sabbath on several occasions. He rejoined in 1997 and helped record the group's final studio album, "13" (2013), before they embarked on a farewell tour that ended with a February 2017 performance in their hometown, Birmingham. His longevity and success have earned him the informal title "Godfather of Metal".