BEFORE Michael J. Fox’s triumphant return to TV, the Parkinson’s disease-plagued actor developed a secret drinking problem that nearly destroyed his marriage!

Booze had such a strangle­hold on the beloved star, it took a dramatic ultima­tum from his devoted wife of 25 years, Tracy Pollan, to break the ad­diction, a source tells The ENQUIRER.

“Michael acknowledges that his Parkinson’s diagnosis sent him over the edge and he coped by turning to alcohol,” said a close source. “But what he hasn’t revealed is that Tracy made it very clear that she wasn’t going to stay in the marriage if he didn’t quit drinking.

“In a vicious fight, she told him, ‘I’m not going to stand by and watch you destroy our family be­cause you’re feeling sorry for yourself.’

“Tracy said that if he couldn’t stop on his own he’d have to enter rehab or seek therapy.”

The 52-year-old former “Spin City” star was diagnosed with Parkinson’s in 1991 at the age of 30. At first, he snubbed treatment to medicate him­self with alcohol while hiding his chronic condition from fans.

In 1998, Fox had brain surgery to help alleviate tremors, and he stopped acting full-time in 2000. He still suf­fers pain, slurs his words and drags his left foot when he walks.

In recent appearances to promote his new NBC sitcom, “The Michael J. Fox Show,” the frail star revealed how he initially ran from his diagnosis and “hit rock bottom.”

“I’d been drinking too much,” he told an interviewer.

“But the diagnosis made me an even bigger idiot. I craved alcohol as a direct response to the need I felt to escape my situation. My boozing, the sub­sequent depression, and my increasing pain isolated me from my wife and my son.”

After one all-night blowout doing tequila shots, Michael said he picked a fight with a close friend. “When I got home,” he continued, “Tracy started crying because she knew I was out of control.

“That’s when Tracy lowered the boom. It was either her and my three-year-old son Sam and rehab – or booze.”

Happily, Michael made the cou­rageous decision to quit, entered therapy and rescued his marriage. He and Tracy went on to have three more kids. He also may have saved his own life.

“Alcohol is extremely toxic to the neurological system and could have made his cognitive and motor functions even worse,” Dr. William Chow, a neurologist at Los Angeles’ Cedars- Sinai Medi­cal Center who hasn’t treated Fox, told The ENQUIRER. “(His drink­ing) could have caused chronic and possible irreversible neurological impairment.”

The actor’s health has improved since he gave up the bottle, but the close source confided: “If Michael hadn’t gotten that wake-up call from his wife, there’s no doubt he’d be long dead from boozing.”