The Piano Man showed up about five minutes before the program's 9:30 a.m. start and took a seat in the back.
"We invited Billy Joel on a lark, but we didn't expect him to come. It was totally thrilling," Nomi Rosen, Deasy's principal, told Newsday.
The concert was held in Glen Cove, N.Y., about 10 minutes from Joel's Centre Island home. He arrived via motorcycle, naturally. "I asked him if he wanted to sit in front, but he said he would rather stay in the back so he wouldn't make the kids nervous," Rosen added.
"These kids will have a story to tell how they got to sing for Billy Joel," Kim Velentzas, 42, of Glen Cove, who was in the audience to see her son Harrison, 7, perform, told Newsday. "For a Long Islander, that's a big deal."