NEW YORK (AFP) - American pop legend Billy Joel married his longtime girlfriend Alexis Roderick in a surprise wedding on Saturday, popping their nuptials on unsuspecting guests at a July 4 Independence Day party, his publicist said.

The wedding, which took place on Joel's Long Island estate, was officiated by New York Governor Andrew Cuomo.

Joel, 66, and Roderick, 33, "surprised guests at their annual July 4th party by exchanging vows in front of their family and close friends", said a statement by the singer's publicist Claire Mercuri.

Among the guests were actor Kevin James and Joel's daughter, singer Alexa Ray Joel, 29 - whom he had with his second wife, former supermodel Christie Brinkley, 61.

The newlyweds are expecting their first child - and the groom's second - in the next few months, the publicist said.

"Congratulations to the glowing bride and groom. And to my daughter Alexa, who has a wonderful friend in Alexis," Brinkley posted on Instagram.

It is Joel's fourth marriage. His first wife was his business manager Elizabeth Weber Small. His third wife was television food critic Katie Lee.

He has been with former Morgan Stanley risk officer Roderick since 2009, the media said.

Speaking to The New Yorker last year, the two said they met at a Long Island restaurant, where each had gone with friends. After he got her number, he phoned her in the restaurant and asked if she would drive him home, he said.

After he got the ride home, he played her Rachmaninoff on a grand piano in the living room. She was quoted as saying by the magazine: "It was like he couldn't not be Billy Joel at that moment."

He was quoted as saying: "I may have got a little fresh."

Although she did not stay that night, they started a relationship months later.

Joel has sold more than 150 million records and has been nominated for a Grammy 23 times, according to his website.

Some of his most popular hits include Uptown Girl, Just The Way You Are and The Longest Time.