A Twitter account called Vegas Gambling Stream says the word on the street is that boxer Floyd Mayweather Jr. is putting nearly $6 million on the Miami Heat tonight in Game 7.

The Heat are seven-point favorites.

**ALERT** Good source from my #HeavyHitters Vegas crew alerted me that Floyd Mayweather has laid over $5,900,000 on Heat -7 tonight in Vegas — Vegas Gambling Steam (@Pregame_Steam) June 3, 2013

While the account uses Pregame (a popular betting site) in its handle, it has no connection at all with the site, we're told. So who knows how much validity this rumor has.

Mayweather is a big-time sports bettor who's always tweeting out pictures of his winning tickets. He's also a Heat fan. This would be the biggest bet we've seen from him.

He's also the highest-earning athlete in the world, and he just inked a deal to fight Canelo Alvarez for a rumored $40 million.

He was in attendance for Game 5 of the Heat-Pacers series. We'll see if he's there tonight.