The Rocky star has revealed his biggest pay days have come from his art collection - not his movie career.
Forty years ago he chose to spend his Hollywood earnings on paintings and those pieces went on to swell in value and confessed he has several pieces at home which are worth more than $US40 million ($A57 million) each.
Stallone admitted he owns pieces by Pablo Picasso and Andy Warhol as well as more contemporary artists.
"That's my weakness. Art ... I do [own] a lot more contemporary artists who are becoming the new [greats] ... George Condo, Rashid Johnson, they're this generation's Picassos," he said during an appearance on The Overlap podcast.
When asked how much his Picasso and Warhol pieces are worth, Stallone replied: "About $40 million ... for just one."
He went on to explain he made a lot of money from art by investing wisely back in the 1980s but regrets not hanging onto his paintings for longer because their value went up by so much.
"I had a collection at one time. I think if you're ever going to make your great fortune, sans technology ... In the middle '80s, I could buy a Monet, that would be $US130,000 ($A186,353)," he said.
"You buy a Picasso, you buy a Renoir ... $US110,000 ($A157,684), Francis Bacon, $US75 ($A108),00 ... The point is I would then sell it for $US3 million ($A4.3 million).
"Ten years later, 12 years later, guys come back and try to sell it to me for $US75 million ($A108 million). I'm not joking," he said.
"So the point is, if you've got art, don't sell it unless you've got to pay the mortgage because it's appreciating. It doesn't cost, you don't have to feed it.
"I had a collection that you can't replace because of the shift in finances. It's unbelieavable.
"There's this one Monet, it's called the Hackstacks, I paid up like $US110,000 ($A157,684). The guy wanted to sell it back to me for like $US130 million ($A186 million)."
Stallone explained his next money making scheme is going to come from collecting vintage watches.
"Oh yeah some of these go for 10 times [what you paid for them] ... That's where I'm going next," he said.
"The vintage Rolex store by John Silver, it's vintage watches, they only sell old Rolexes and for some reason I've fixated on a watch called the Stella ... but they're hand painted and I've got just about the whole collection."