Billy Joel chose the Fourth of July to say 'I do' to wife No. 4 in a super secret ceremony at his Liong Island estate.

Joel and Alexis Roderick, who at 33 is half his age, exchanged vows in front of New York Gov. Andrew Cuomo, a close friend of the Piano Man.

The couple have been dating since 2009 and in April revealed that she is expecting later this summer.

This will be the first child for Roderick, who is an analyst at Morgan Stanley; and the 66-year-old Joel's second. He and actress/model Christie Brinkley are the parents of 29-year-old songbird Alexa Ray Joel.

The ever-gracious Brinkley, 62, remains close friends with Joel.

On Instagram, she wrote: "Congratulation to the glowing bride and groom. And to my daughter Alexa, who has a wonderful friend in Alexis! Wishing the growing family every happiness!"