Mayweather vs. McGregor Prop Bets: Bank on Demi Lovato's Boobs!!

Lookin' to make some extra cash during the Floyd vs. Conor fight?? BET ON THE BOOBS ... 'cause Demi Lovato's twins highlight the fight's list of prop bets!!

The cyber-gambling site BetOnline.ag -- one of the biggest gambling sites on the net -- is offering up a bet on whether Demi will show cleavage or cover up the goods during "The Star-Spangled Banner" before the fight.

As of right now ... the odds are definitely pro-boob:

Yes +350 (bet $100 to win $350)

No -500 (bet $500 to win $100)

There's more (not as sexy) bets ... like over/under 1 min 52 seconds for her rendition of the anthem and whether the Biebs and Lil Wayne will make an appearance.