At the 100th birthday party for Mary Morello, mother of Rage Against the Machine guitarist Tom Morello, actor and Tenacious D frontman Jack Black joined a kid band to perform a cover of Ozzy Osbourne's chilling hit "Mr. Crowley."

Morello shared a nearly eight-minute video on Instagram, calling the performance a "stirring rendition" of the Blizzard of Ozz classic. It appears mom quite enjoyed it as well as her son notes, "Mary was pleased!"

Perhaps that's because Tom's son/Mary's grandson Roman was on guitar!

Morello shouted out the members of the band, which features 12 and 13-year-old musicians, including the aforementioned Roman, as well as Yoyoko Soma (a Japanese drummer who has garnered internet fame), Roya Feiz (bass) and Hugo Weiss (keyboard).

READ MORE: Watch Tom Morello's Mom Introduce Rage Against the Machine as 'Best F--king Band in the Universe' in 1996

Black's nasal-toned voice is perfectly suited for the Ozzy cover and the youngster band clearly has quite a lot of talent, drawing parallels to the 2003 hit movie School of Rock, where Black's character Dewey Finn inspires a group of young students to learn their instruments and rock out.

Watch the performance below.

From all of us at Loudwire, we wish Mary Morello a very happy 100th birthday!!!

Jack Black + Kid Band Cover Ozzy Osbourne's "Mr. Crowley" at 100th Birthday Party For Tom Morello's Mom Mary

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