There's just one catch -- Iron Mike wants a BILLION dollars.

55-year-old Tyson made the comments on his "Hotboxin'" podcast this week ... when his convo with boxer Jermell Charlo and Boston Celtics legend Paul Pierce turned to a rumored fight against Jake.

Pierce said he heard Mike was going to fight Jake, but Tyson seemed to be unaware of the rumor.

"Nobody told me that," Tyson said. "Hey, I ain't got no f***ing money. So, where's the f***ing contract?"

"I've never heard this from nobody, I've just heard this from you guys."

Now, Tyson and Paul are buddies.

In fact, you could argue Jake owes at least some of his boxing success to Mike. The Problem Child's career exploded after he flatlined Nate Robinson on the Tyson-Roy Jones Jr. undercard in November 2020.

The men have become good friends ... and Mike even said they were recently together in St. Barts, where they partied.

When Pierce asked Mike if he'd ever fight again, specifically against Jake, Tyson quickly said "a billion bucks" ... setting his price tag to fight Jake.

Tyson previously denied reports he was in "advanced talks" to fight Jake in a $49 million boxing match ... though his latest comments seem to suggest the fight isn't totally off the table.