BILLY JOEL has a new muse.

    The “Piano Man” singer and his wife, Alexis Roderick, welcomed their first child together — a daughter — on Wednesday, according to People magazine.

    That means Joel has become a father for the second time at the age of 66. His daughter with Christie Brinkley, singer Alexa Ray Joel, is 29. She’s been the inspiration for some of her father’s songs through the years, including “Lullabye (Goodnight, My Angel)” and “Downeaster Alexa,” which is about a boat he named after her.

    Joel and Roderick, 33, were married July 4 at a surprise wedding at his sprawling Center Island, New York, estate. The 40 or so guests thought they were attending the singer’s annual Fourth of July barbeque, but then New York Governor Andrew Cuomo, a longtime friend, presided over a vow exchange.

    The crooner and Roderick, an equestrian who was previously an exec at Morgan Stanley, have been dating since 2009. She is his fourth wife.(SD-Agencies)