Film Producer Jon Peters Betting $5 Million On Jake Paul To Beat Anthony Joshua

There's a LOT on the line when Jake Paul and Anthony Joshua enter the boxing ring in 17 days -- not only is El Gallo hoping to pull off the unthinkable and beat a former heavyweight champion ... but one very famous bettor is looking to cash in BIG on an upset.

TMZ Sports is told ... former Sony Pictures head Jon Peters is all-in on the YouTuber-turned-fighter's chances against A.J. on Dec. 19 -- to the tune of a whopping $5 MILLION wager.

So ... why all the confidence in the Disney kid?? We're told Peters and Paul recently had a lengthy chat about the bout ... and the film producer (with flicks like "Flashdance," "A Star Is Born," and "Batman" to his name) was fully convinced.

We're told Paul assured Peters he's "gonna kick the s*** outta [Joshua]" at the Kaseya Center in Miami ... and that was music to his ears.

The insane amount of dough could really pay off if Paul is victorious -- depending on the odds Peters placed it at, that five milli could turn into a profit between $30-45 MILLION.

Paul's currently a +650 underdog against Joshua ... meaning a $100 bet would get ya $650 if he's victorious.

We're told Peters has plenty of people telling him he's crazy for the bet ... but he's heard that plenty of times -- including when he decided to make ASIB with Barbra Streisand.

Peters actually joined Harvey, Charles and Lucas on "TMZ Live" to discuss his decision ... and he revealed his whole family is placing bets on Paul -- and they could walk away with $50 MILLION total!!