Jack Black, along with a group of talented 12- and 13-year-olds, covered Ozzy Osbourne’s ‘Mr. Crowley’ at a recent 100th birthday party.

You read that correctly.

But it wasn’t just anyone’s 100th birthday, it was The Rage Against The Machine guitarist Tom Morello’s mum Mary’s 100th birthday.

The Tenacious D frontman led the band on vocals, giving his best Ozzy impersonation while Morello’s son Roman showed off his skills with some seriously impressive solos and playing the guitar behind his back:

 

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And according to Morello’s Instagram post, “Mary was pleased!”

Morello has always spoken highly of his mother, who’s been an activist all her life. He’s shared fascinating stories about her over the years:

“In the 1930s, she helped feed hobos during the Great Depression and supported the coal miners struggle to organise,” he previously wrote.

“In the 1940s, she helped raise war bonds to defeat the fascists in WWII. In the 1950s, she taught international students and opposed racist Jim Crow laws and, as a single woman, she’s traveled to over 60 countries.

“In the 1960s, she aided anti-colonial movements while living in Africa. In the 1970s, she was a radical teacher in a conservative high school inspiring students to challenge the system, and aided the United Farm Workers and the Urban League.

“In the 1980s, she went on nine peace missions to the Soviet Union and Cuba. In the 1990s, she opposed the first Iraq War and founded an international organisation to oppose music censorship called Parents For Rock and Rap.

“In the 2000s, she helped homeless people and recovering addicts get their high school diplomas at the Salvation Army and opposed wars for oil. In the 2010s, she volunteered at local soup kitchens and currently works with Doctors Without Borders and Mideast peace organisations, still feverishly writing letters to the editor, all the while being a loving grandparent.”