In a joint statement, the Joels confirmed the split, noting that it was "the result of much thought and consideration".
"Billy and Katie remain caring friends", the statement continued as reported by the NY Daily News
, "with admiration and respect for each other."
The news follows on from reports earlier in the year in regards to Mrs. Joel's involvement with thirty-six year old fashion designer, Yigal Azrouel. In January, the two were reportedly spotted together dancing in Miami, Florida.
A spokesperson for Mr. Joel, however, insists that "their decision to separate was absolutely unrelated" to anything involving Azrouel.
The couple have split after five years of marriage. Joel met Katie at a party in New York in 2003. The couple married one year later, with Joel's daughter Alexa Ray serving as maid of honour.
This was Katie's first marriage, whilst the Piano Man was formerly married to his then-business manager, Elizabeth Weber Small (1973-1982) and model Christie Brinkley (1985-1994).