Philip Glass performing inside of a Richard Serra installation? Now we've seen everything! The composer will team up with his old pal (who he was once an assistant for) on June 27th, for a once-in-a-lifetime concert inside of Serra's current installation at David Zwirner Gallery.

First, a little more on the Glass/Serra bromance, which bloomed in the '60s—per a 2002 New Yorker article:

“Phil took me to see Buster Keaton films, which I'd never seen before, and I took him to Brancusi's studio,” Serra remembers. Serra spent a lot of time sketching in Brancusi's studio, which had been re-created in the Musée d'Art Moderne de la Ville de Paris. “It was the first time I looked at sculpture seriously,” he said. “I really responded to the strength and simplicity and abstraction of the work. I just found myself being drawn back to that studio every day.” In the evenings, he and Glass would go to La Coupole and stare at Giacometti.

According to ArtsBeat, at the June event, "Mr. Glass and the violinist Tim Fain will play a special concert inside Mr. Serra’s heavy-duty installation, Richard Serra: Equal, a grouping of 40-ton stacked, forged-steel cubes" (which are on view now through July 24th). The intimate concert will benefit House With Heart, and tickets (available here) cost $300 and $1,000.

After the show go watch Koyaanisqatsi inside the Astor Place Cube.