Sometimes, what happens in the wings of a theater can tell as big and as fascinating a story as what happens front and center on the stage itself.

That seems to be the case with SSU’s Green Music Center, where stars and celebrities the likes of Tony Bennett, Wynton Marsalis, Elvis Costello, Jessye Norman and Yo-Yo Ma have wowed the audience. But what most music lovers and opera fans don’t know is that almost every performer who has appeared on the stage is part of a backstage exhibit.

Their autographed publicity photos, along with the oversized banners used to advertise their concerts and recitals now hang on the walls behind the Green Center’s stage, though so far only VIPs and guests on special tours have been able to enjoy them. In a way they’re a kind of mini-museum.

The idea belongs to Larry Furukawa Schlereth, SSU’s chief financial officer. He visited New York’s Carnegie Hall, was delighted by the autographed celebrity photos on the walls and decided it was too good an idea not to borrow and bring back home.

For three years now, performers at Weill Hall have taken out their fountain pens and Sharpies, scrawled their names — illegibly as well as legibly — and written brief Valentines to SSU, to benefactors Joan and Sandy Weill and to the GMC itself.

“How wonderful!,” crooner Tony Bennett gushed, adding, “May you please invite me here again.”

Mandolinist and composer Chris Thile wrote, “I wish I could tour with Weill Hall.”

Vocalist Cecile McLorin Salvant drew a cute cartoon of herself. Yo-Yo Ma, the French-born Chinese American cellist, added a whimsical mustache to his upper lip.

Comedian Bill Maher wrote “Bill Maher” in big letters. Saxophonist Dave Koz scrawled, “We had a blast.”

Robin Freeman, the Center’s communication manager, says the posters brighten her day every day of the week and add to the renown of Weill Hall.

“We’re a very new building,” she says. “But we already have a very rich history.”

Perhaps it’s time to open the back doors and allow the public to see the exhibit before or after they attend a concert.