Watch Johnny Depp and Gene Simmons Rock Out for Charity

The room was packed when Johnny Depp joined KISS legend Gene Simmons onstage on Sunday for a live rock performance at the Lucky Strike bowling alley in Hollywood. Tickets for the exclusive event weren’t easy to come by – they cost $150 each – but the high prices raised money for a good cause: MendingKids.org, which funds corrective surgeries for children whose families can’t afford them.

According to the Associated Press, Depp, 52, stepped onstage without speaking a word to help the band play the Alice Cooper classic “School’s Out.”

“Mending Kids is not only changing the lives of these kids, but making a difference in developing countries that are in need of medical care,” Depp later said in a statement.

Speaking to Billboard, Simmons, 65, said he’d never played with Depp before, and that he and the rest of the performers improvised the show.

“You get up there and just let it roll,” he said. “But anything you do too slick doesn’t come off heartfelt. It’s less about the show and the celebrities and more about the good and what we’re all trying to do for kids.”

At one point, Simmons invited anyone with $1,000 to donate to the cause to come onstage and sing “Rock and Roll All Nite” with the band. About 10 audience members did, including Simmons’ son and daughter.

The event also saw the rock band Extreme reuniting onstage to play their 1991 hit “More Than Words.”

Depp announced last week that he would be performing with the rock supergroup Hollywood Vampires, which includes Cooper and Aerosmith’s Joe Perry as well as bassist Duff McKagan and Matt Sorum, formerly of Guns N’ Roses. The band is only playing two U.S. shows, both in Los Angeles, and then one in Brazil. Sales of the band’s forthcoming album will benefit the Grammy Awards-affiliated charity MusiCares.

This article originally appeared on People.com.