Fiat heir allegedly goes on drug, alcohol binge — then fakes own kidnapping to pay for it!

NEW YORK — How do you spend a holiday weekend when you're the heir to the Fiat auto fortune and got more money than you know what to do with? You turn up!

And then stage your own kidnapping, to boot!

"I like to see that my money is well spent, not overspent," Fiat heir Lapo Elkann said in a jet-setting Instagram video.

Well, that's allegedly just what the 39-year-old playboy did...now that he's been charged with filing a false report.

But it gets a whole lot weirder than that! The rich bad boy flew into the Big Apple Thursday and reportedly started searching for an escort.

"I don't like vulgarity, and I don't like tackiness," Elkann continues in his Instagram video, showing off his flair for fashion. "I don't like bad taste, but I don't judge."

Elkann might need to re-think that since he apparently spent two days on a wild party binge with a transgender escort!

The escort allegedly supplied Elkann with plenty of cocaine, pot and alcohol, but after the party boy ran up a hefty tab of $10,000, the dealer decided to reach out to a family member, according to authorities.

Elkann allegedly claimed he had been kidnapped so he could get a ransom pay-off to pay off his tab, but authorities said the plan backfired when the relative called the police, instead!

Now Elkann gets a date in court in January...

Can you say, 'The party's over?!'