Billy Joel’s 100th Madison Square Garden concert on Wednesday night was a New York City metro area spanning event, bringing Long Island together with New Jersey.

In a total surprise for the sold-out crowd, Bruce Springsteen joined Billy on stage for a couple of songs.

The Boss sat atop Joel’s piano on Bruce’s “Tenth Avenue Freeze-Out,” then grabbed his guitar for “Born To Run” with Billy still on keys.

No artist has played MSG as many times as Joel. His monthly residency there began in 2014 and it runs through at least December of this year.