Billy Joel surprised students of a Long Island elementary school by showing up at their Piano-Man themed spring concert.

The principal of Glen Cove's Deasy Elementary School says the school invited Joel on a lark but didn't expect him to come.

"The River of Dreams: A Billy Joel Tribute" concert on Wednesday featured the children singing 15 of the Piano Man's songs. Kindergartners led off with "You May Be Right," first-graders sang "Movin' Out," and then second-graders stepped up with "We Didn't Start the Fire" and "New York State of Mind."

Joel arrived on his motorcycle from his nearby home in Centre Island.

He entered the auditorium five minutes before the concert started at 9:30 a.m. and applauded, smiling, at the end of every song.

The school's concert director and music teacher Rosita Mallo says she learned Joel was in the audience minutes before the concert was to start.

She told Newsday: "It totally freaked me out. My nerves went sky-high."