BILLY JOEL’s ex-wife CHRISTIE BRINKLEY is at war with his live-in girlfriend over his boozing!

The former supermodel des­perately wants to stage an intervention to help the Piano Man kick the habit for good, but those closest to him refuse to get involved – and his lover, financier Alexis Roderick, believes Christie is be­ing a “control freak,” says an insider.

The 64-year-old music superstar, who’s done stints in rehab in 2002 and 2005, but denies he has a drink­ing problem, was spotted earlier this year drinking red wine at a Florida restaurant. Then, looking bleary-eyed, he hopped onto his motorcycle.

Scared for his life, Christie – who has remained close to the six-time Gram­my winner since their 1994 divorce – began sounding the alarm.

“Billy is playing with fire by continuing to drink,” a friend confided to The ENQUIRER. “He’s semi-retired now and plays very few concerts. Christie knows Billy, and when he’s bored he turns to drinking.”

Christie has reportedly discussed Joel’s drinking with their 27-year-old daughter Alexa Ray as well as Alexis, 31.

“But she can’t find one person who is willing to stand up with her and stage an intervention,” said the friend.

“Alexis believes Christie may be well-meaning, but thinks she’s being a control freak and that Billy can handle his drinking now. She tells Christie until she really sees a problem, let him have his glass of wine – he’s earned it.

“Alexa doesn’t want to confront her dad, either. She wants to maintain a good relationship. But there’s a big fear that Billy’s headed down a slippery slope by drinking at all.”