Jack Black showed his heartwarming kindness when the comedic actor and Tenacious D singer personally belted a classic School of Rock song for a young fan in palliative care at TrinityKids Care in Los Angeles.

The streetside serenade happened Oct. 8 at the Layla Paige and Friends Walk for TrinityKids Care, a fundraising hike hosted by Black for the pediatric hospice. Abraham, a 15-year-old with a rare disease called Pearson syndrome, is the child to whom Black sings, as footage captured by his mother shows.

Watch the video down toward the bottom of this post.

This year, over 500 walkers joined Black for Layla's Walk 2022. The fundraiser celebrates the life and legacy of the late Layla Paige and all patients who've been assisted by TrinityKids. In 2017, Paige died from a brain disorder at the age of 2.

"In the End of Time," a centerpiece of Black's School of Rock performance from the 2003 film, is the excerpt the actor sang for Abraham. It's memorable refrain from the movie is, "You're not hardcore / Unless you live hardcore."

"Abraham got to meet Jack Black and sign his favorite part to his Favorite movie 'School of Rock,'" Abraham's mother, Veronica, said in a post. She added, "trinity care kids and @Jack Black making this all happen!!"

Black didn't always bring such excitement with his songs, however. In fact, back in the early days of Tenacious D, the acoustic comedy duo that includes guitarist Kyle Gass was once booed onstage by an audience waiting to see headliners Stone Temple Pilots.

The year was 1999. The place was Las Vegas. The show? "The Miller Genuine Draft Blind Date — do you remember this?" Black told Loudwire earlier this year. "All of these people would win their tickets and fly in," he explained, "and they would get drunk as fuck on Miller Genuine Draft."

The gimmick, however, was that attendees wouldn't know what band was playing until they hit the stage. And while Tenacious D have since become a metalhead stoner favorite, they were still new in 1999. (Only their first series of HBO shorts had hit the airwaves at the time.)

"They're all thinking, oh my God, it's gonna be fuckin' U2 or something," Black recalled. Mimicking the subsequently angry response, he remembered, "The curtain opens, and it's Tenacious D, and everyone in unison just starts booing. Fuck you! You suck! Who are you? This is not a blind date that I like!"

Jack Black Sings to Young School of Rock Fan - Oct. 8, 2022

The Most-Replayed Scenes From the 20 Most Popular Rock + Metal Videos

These are the scenes you keep watching over and over.

More From Classic Rock 105.1