Paul Simon walked onstage to a rousing ovation in a royal purple jacket for a casual downtown evening — as laid back as something with about 150 guests could be — at the SoHo Sessions loft in NoLIta on Monday just after 8 p.m. for a small benefit concert.

“Today is my birthday,” said Mr. Simon with a mischievous, boyish smile, drawing more cheers. He quickly added, “It’s not my birthday.” (He’ll be 83 in October).

Earlier, the venue’s runners escorted guests — including Whoopi Goldberg, Kevin Bacon, Amy Schumer, Jerry and Jessica Seinfeld, and the musician Jackson Browne — in the updated freight elevator to the loft, a 3,500-square-foot fifth-floor space that was the original site of Chung King Studios, a former recording studio.

Since December 2021, Nicole Rechter and Greg Williamson, two concert producers, have curated 14 Soho Sessions — private, mini-concerts raising funds and awareness for various causes, including mental health and gun control, and building community around the music. Ms. Rechter and Mr. Williamson are also behind the annual Love Rocks NYC, benefiting God’s Love We Deliver.