Floyd Mayweather Signs On For Major Celeb Boxing Event, But Not to Fight

There is a HUGE celebrity charity boxing match in the works -- with some big names being thrown around ... and we've learned Floyd Mayweather is now involved.

Our sources tell us ... the combatants are big stars -- we've seen the list but we're being told there's still a matter of locking everyone up.

One of the people involved is Floyd -- but we're told he will NOT fight ... instead, our sources say he'll be one of the judges, tasked with scoring the fight.

As for the fighters themselves, we can't give it away yet -- but 2 of the names are big boxing stars and others are from the NBA, Hollywood, comedy and MMA.

We're told event organizers are targeting the end of June at a venue in Las Vegas ... and they're working with health and wellness website Celebrity Sweat to put the whole thing together.

One source tells us the event is tentatively being called "Fight for a Cause" and will raise funds for the U.S. Military charities and COVID-19 relief.