‘Piano Man’ Billy Joel Hits a Bum Note!

Alexis roderick alexa ray joel billy joel sq

The “Piano Man” is about to become a 66-year-old “Piano Daddy” once more – but Billy Joel’s daughter isn’t ready to give up being her father’s only child!

But the papa-to-be pop star just rocked Alexa Ray Joel’s plans to solely inherit Billy’s $180 million fortune!

And sources told The National ENQUIRER that Alexa’s mom, Christie Brinkley, is also unhappy about Billy having a kid with 33-year-old girlfriend Alexis Roderick.

“The news caught them completely off guard,” said an insider.

“Billy hasn’t even married his girlfriend yet – and she’s already pregnant, and there’s no doubt she’ll want the child to share in a large chunk of Billy’s estate!”

Christie, who split from the singer in 1994, had always expected their 29-year-old daughter would inherit everything from Billy.

“Alexa has faithfully been at her dad’s side her whole life, through his messy marriages and his personal problems,” dished the family friend.

“Now she’s no longer the only kid in the picture – and, truth be told, it rubs her the wrong way that Alexis is only a few years older than her!”

Meanwhile, the family of Billy’s baby mama couldn’t be happier.

Alexis’ brother, Bruce Roderick, told The ENQUIRER: “I’m very happy for them. Billy’s a wonderful guy.”