Billy Joel commemorates his 100th show at Madison Square Garden with a surprise guesting from Bruce Springsteen. The latter went on stage while Joel was singing Springsteen's songs.

Joel sang "Born to Run" and "Tenth Avenue Freeze-Out" for his fans during his show in New York City. Springsteen performed with him at around 10 p.m. One fan, who attended Joel's show, detailed what transpired on Wednesday night.

"[Springsteen] appeared ready to rock but his performance on 'Born to Run' was not as strong as we are used to. He had the crowd in his hand in 'Tenth Avenue.' The crowd went nuts, they really did," said Tim Jackson.

The fan also revealed that Springsteen sat on Joel's piano as they did a duet of "Tenth Avenue Freeze-Out."

Bruce Springsteen's Netflix Show

Springsteen is also filming his performances as part of the Springsteen on Broadway at the Walter Kerr Theater this week. The venue of his filming is just about eight minutes away from Madison Square Garden.

Springsteen on Broadway will premiere on Netflix on Dec. 15.

This is not the first time that Joel and Springsteen performed together. In 2016, they also performed at the Veterans Day in Wall.

Christie Brinkley Talks About Ex-Husband Billy Joel

In related news, Joel's ex-wife, Christie Brinkley, opened up about raising their daughter, Alexa Ray, together despite their divorce.

"Whenever Billy would sit down to play - even when Alexa was a little baby - I would lay her down on the piano so that the music would literally vibrate throughout her entire body. Alexa would feel the chords of the music and she loved it," said Brinkley.

Joel and Brinkley were married from 1985 until 1994. There were several reports claiming that Brinkley was Joel's inspiration for his hit 1983 single "Uptown Girl."

Despite her parents' divorce, Alexa Ray grew up close to both Joel and Brinkley. She and her dad love to sing in front of thousands of people.

"Their voices sound great together. Even though Alexa was performing in Madison Square Garden, she made it feel very homey, which is something that her dad has always been able to do. He can make any space feel as comfortable as a living room," said Brinkley.

Joel is an American singer, songwriter, composer, and pianist. He has been dubbed as the Piano Man of America. In 1972, he signed with Columbia Records following his live radio performance of "Captain Jack."