Billy Joel married girlfriend Alexis Roderick in a surprise ceremony at the couple's annual Fourth of July party.
New York Gov. Andrew Cuomo presided over Saturday's nuptials at Joel's Long Island estate, the singer's spokeswoman Claire Mercuri said.
The small group of family and friends at the party didn't know the couple planned to exchange vows. Among those in attendance were Alexa Ray Joel, his daughter with his second wife, model Christie Brinkley, and actor Kevin James.
People magazine first reported the wedding.
Joel, 66, and Roderick, 34, have been dating since 2009 and are expecting their first child. This is his fourth marriage.
Joel is currently on tour. On Wednesday, he set a record for most performances by a single artist at Madison Square Garden with his 65th show, besting Elton John.