JOHNNY DEPP is facing the world’s biggest-ever palimo­ny case over his $350 million “Pirates of the Caribbean” treasure chest from spurned lover VANESSA PARADIS.

Furious over bombshell reports that the heart­throb actor has been wildly partying and se­cretly romancing a string of beautiful women, Johnny’s longtime French lover Vanessa Paradis is demanding an equal share of his movie millions, say friends.

At 49, the superstar has become Hollywood’s highest-paid actor – rak­ing in more than $20 million a film. In 2010 alone, he reportedly made a whopping $100 million.

“Vanessa is gunning for Johnny,” revealed an insider. “She played a big part in his success and for years they shared everything. It’s only in recent months that they’ve lived separate lives.

“Vanessa hears about all these other women, and Johnny’s drinking and partying, and she can’t help wondering how long it’s been go­ing on. And career-wise, while he was becoming a major movie star, she took a seven-year break from recording albums.

“Just because they never got mar­ried doesn’t mean she shouldn’t have the same rights as a wife. She feels she deserves a hefty portion of that $350 million fortune.”

Vanessa, 39, might snare a big chunk because they were together when Depp made most of his money, say sources.

His career didn’t soar until he was cast as Capt. Jack Sparrow in Disney’s “Pirates” franchise, and that was five years after he started romancing her in 1998.

In addition to their millions, the couple owns homes in the South of France and in Venice, Italy, as well as one in Britain and two in Los Angeles.

They also own an is­land in the Bahamas as well as a yacht.

But friends told The ENQUIRER that the French actress and singer feels she sacri­ficed her once blossoming career to be Depp’s partner and help raise their two kids, Lily- Rose, 13, and Jack, 10.

Famed divorce attorney Raoul Felder believes Vanessa is in for a huge payday.

“Even though Johnny and Vanessa never married, factoring in the length of their relationship – 14 years – as well as having two kids together, she could walk away with millions in pali­mony and maintenance,” he told The ENQUIRER.

As recently as last sum­mer, Vanessa sported a diamond “the size of the Ritz” on her ring finger, according to a published report.

And that ring will carry a lot of weight in any palimony battle, noted the New York-based attorney.

“What is key to this case, compared to other unmarried couples, is that she has a ring from him,” Felder said. “That is likely to make a big difference.”

In recent months, Depp has been linked to 26-year-old Amber Heard, his bisexual co-star in “The Rum Di­ary,” as well as to his sexy “Dark Shadows” co-star Eva Green, 31.

The ENQUIRER has also reported that Johnny enjoyed steamy on-set chemistry with Angelina Jolie while making “The Tourist” in 2010, and the actor was reportedly spotted in February leaving Ashley Olsen’s New York loft.

“It’s all been tremendously heart­breaking for Vanessa,” said the insider. “Now she wants her just due – in millions.”