The film spans four decades of Ozzy’s career as a rock musician, including some of his own personal struggles which have been shrouded in secrecy.
Joined by mom Sharon Osbourne and brother Jack Osbourne, The 26-year-old reality star looked slimmer than ever, wearing a short printed dress for the Hollywood event.
Jack produced the documentary, which charts Ozzy’s troubled youth, drug addiction and rise to fame with Black Sabbath.
His sister Kelly urged people to give him their support, tweeting: “EVERYONE tweet @MrJackO and wish him good Luck for tonight!!!”
The film includes never-seen-before onstage footage and interviews with the Paul McCartney, Tommy Lee and members of the Osbourne family, including his wife Sharon.
The film premiered earlier this year at the Tribeca Film Festival.