At City Winery on Varick Street, near Seventh Avenue South, people get to see more than a famous musician on stage; they get a chance to break down the barriers between the stage and the audience as part of Guitar Mash.

"Guitar Mash is a non-profit I founded a few years ago with a mission of returning music to its social roots,” Rebecca Weller, Guitar Mash’s founder, said. “It is a very simple idea; it is people sitting, playing, and singing together."

Attendees can bring their acoustic guitars or simply sing along in the group performances.

Two performers at the Fourth Annual Guitar Mash Benefit Jam, which is using ticket sales to benefit community music programs, will be Jackie Greene of The Black Crowes and 12-year-old Brandon Niederauer from the new Broadway musical "School of Rock."

"Four years he’s been playing, and the kid is ripping," Greene said about Niederauer’s guitar play. "That’s unbelievable."

"The fact that you can get so many sounds on one instrument, and the fact that so many people love it, it’s just one unifying thing. This small instrument unifies the entire world," Niederauer said, referring to his guitar.

While Greene and Niederauer have a ton of star power, Greene said what’s really important is what happens in the audience.

"It’s going to be a total trip to have like 300 guitars," The Black Crowes singer and songwriter said. "You know, they’re going to be louder than we are on the stage, and I think it’s going to be really cool — a really cool juxtaposition of a changing in roles."

The Fourth Annual Guitar Mash Benefit Jam will be Sunday. Tickets start at $50 and are available at guitarmash.org, along with the set list and music charts.