Celebs are pouring into T-Mobile Arena with the minutes ticking away to Mayweather vs. McGregor ... and it’s a roster fitting for the Fight of the Century.

A suited LeBron James came through with his wife Savannah ... and he wasn’t the only superstar athlete in attendance.

Alex Rodriguez and Jennifer Lopez -- decked out in all white -- might have had the freshest ride to the arena ... courtesy of Patriots owner Robert Kraft and his private jet.  

Names like Bruce Willis, Vanessa Hudgens and Meek Mill are also live in Vegas to take in the fight.

No surprise -- they're all lookin' good. But who's the best dressed?

THE KING HAS ARRIVED