Billy Joel has split from his third wife.

The 'Piano Man' singer - who was previously wed to his business manager Elizabeth Weber Small and supermodel Christie Brinkley - and chef Katie Lee Joel have ended their marriage but insist the break-up is amicable.

Billy's spokeswoman said: "After nearly five years of marriage, Billy and Katie have decided to separate. The decision is the result of much thought and consideration. Billy and Katie remain caring friends, with admiration and respect for each other."

She also denied claims 27-year-old Katie's close friendship with fashion designer Yigal Azrouel was the reason behind the split from Billy, 60.

The spokeswoman added: "Their break-up has nothing to do with Yigal. Their decision to separate was absolutely unrelated to Yigal."

Friends of the New York- based couple - who married in October 2004 - claim the 33-year age gap between the pair played a big part in the separation.

One pal said: "It was really the age difference that caught up with them. They grew apart. She is very career-oriented. She loves going out. She loves the city. When Billy isn't touring, he'd rather be on Long Island with his motorcycles and boats."

Billy's daughter with Christie, Alexa Rae Joel, is supporting her musician father through the break-up

She said: "He was the first person that told me, being who he is, he can't just trust everybody. I like knowing that my dad can talk to me in the same way that I come to him... I'm just supporting him right now."