McCartney and Joel came together to sing "Get Back" and "Birthday," the latter of which Sir Paul sent out to "anybody who's got a birthday anytime this year."
"Rockin with the Magic Piano Man," read a post to McCartney's official Instagram and Twitter pages after the surprise collaboration. Joel played McCartney's brightly colored upright piano during the mini set while McCartney played his signature Hofner violin bass.
Check out some fan-shot footage above!
McCartney famously flew from the UK to Queens, New York, in 2008 to perform with Joel for his Last Play at Shea concert, the final music performance at Queens' Shea Stadium before the structure was demolished to complete Citi Field.
The McCartney/Joel collaboration comes about a-week-and-a-half after McCartney brought Bruce Springsteen and E Street Band guitarist "Little" Steven Van Zant out for an encore at Madison Square Garden.