Jack Black and Kids Cover Ozzy Osbourne for Tom Morello of Rage Against the Machine’s Mom's 100th Birthday

The actor joined Tom Morello's son Roman and other pre-teen musicians for a performance of "Mr. Crowley"

Jack Black went full School of Rock for a sweet celebration.

The actor/singer, 54, attended a celebration for the 100th birthday of Rage Against the Machine guitarist Tom Morello’s mother, Mary Morello, and performed a cover at the event. Along with a band of 12 and 13-year-olds, including Morello’s son Roman Morello, the comedian covered Ozzy Osbourne’s 1980 classic “Mr. Crowley.”

The Rage Against the Machine musician, 59, shared footage of the performance from over the weekend on Tuesday.

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In the clip, the Tenacious D band member joins a pre-teen guitarist, drummer, bassist and piano player on a makeshift stage — and they all absolutely shred through the iconic metal song. Black, who was dressed in a matching shirt and shorts combo with a flame design, took on vocals. He showed off his gritty, soulful rocker pipes, while dancing and throwing up the sign of the horns hand gesture throughout the song.

The entire band kept it fierce and tight. As Morello’s son on guitar performed a solo — even playing the instrument over his head — the entire room cheered, and the School of Rock actor joined him by encouragingly rocking out alongside him.

“What an amazing mom and what an amazing life,” Black shared at one point.

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In the caption of his Instagram post featuring the video, Morello called the performance “a stirring rendition” and shouted out each of the performers. “Mary was pleased!” he said, referring to his mother who turned 100 on Oct. 1.

Morello also paid tribute to his activist mother with several posts on Instagram over the weekend, including a photo of her edited onto a cover of TIME.

“HAPPY 100th BIRTHDAY TO MY MOM, THE EXTRAORDINARY MARY MORELLO! Love you mom!” the recording artist wrote in the caption.

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He continued to honor her with a carousel of photos of her taking part in protests and charity work, sharing in the caption how much she’s inspired his own activism. “This retired public school teacher from a family of Illinois coal miners has led a humble yet powerful life,” Morello shared. “When I asked her what her philosophy of life was she said, ‘To recognize people have needs and to help them. You accept everybody. You think everybody is equal. And you help whoever you can. That’s my philosophy.’”

He added, “As the most popular and radical member of the Morello family it’s no surprise she had friends & family from six continents at her party yesterday.”

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Earlier this year, the guitarist also gave her a shout out on Mother’s Day.

Black recently wrapped up his North American Tenacious D and the Spicy Meatball Tour. He and bandmate Kyle Glass kicked off the live dates in summer after they released their latest single “Video Games” in June.

Next year, they’ll take their show to Europe and the U.K. beginning in April.

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