It isn't a boxing match without some serious headliners, and Conor McGregor's bout with Floyd Mayweather is no exception. T-Mobile Arena is filling up and the stars are out in Las Vegas. From NBA stars to movie megastars to boxing legends, some of the most well-known faces in the United States are in Vegas to let off some steam and watch the main event.

Perhaps the most recognizable face in the building, LeBron James made his grand entrance.

In addition to LeBron, the Ozzy and Sharon Osbourne are also in attendance. Jamie Foxx and Olivia Munn turned heads, as well as boxer Danny Garcia and UFC legend Tito Ortiz.

Some other stars filed in, including Julius Erving, Diddy, Ray Lewis and Paul Pierce. Danny Garcia also made an appearance.

Last but not least, Demi Lovato. She sang the anthems before the fight.

More stars will turn up as we get closer to the fight, but the time for play in Las Vegas is nearly over. Soon, all eyes will be on McGregor-Mayweather to determine whether boxing will get a new king live on Showtime PPV.