Demi Lovato will sing the US national anthem at floyd mayweather and Conor McGregor's epic boxing bout.

The 25-year-old star will take to the stage at the T-Mobile Arena in Las Vegas on Saturday (26.08.17) to belt out the iconic 'Star-Spangled Banner' tune ahead of one of sport's most hotly-anticipated events of all time between the professional boxer and the UFC fighter.

A tweet on the account of Mayweather Promotions - of which Floyd is president - read: ''.@ddlovato set to sing the National Anthem prior to Floyd & Conor making their way to the stage on fight night! (sic)''

TV channel Showtime also tweeted: ''Excited to have #Grammy nominated and multi-platinum global artist @ddlovato sing the National Anthem at #MayweatherMcGregor! (sic)''

Demi confirmed the news by retweeting both of the messages on her own Twitter account, and it won't be the first time she has performed the US national anthem.

The raven-haired star sang the famous tune at game four of Major League Baseball's 2015 World Series, game five of the 2011 World Series and at an American football game involving the Dallas Cowboys in 2008.

But it will be the first time she has performed the song at a boxing match.

Demi will be joined by a host of stars at the so-called ''Fight of the Century'', including Angelina Jolie, Charlize Theron, Mark Wahlberg, Drake, Denzel Washington and L.L. Cool J.

Some celebs are expected to arrive in Vegas earlier this week, and that certainly seems to be Demi's plan.

She tweeted: ''See you on Thursday in Vegas?? We're shooting something special with @MTV (sic)''

Actor Jamie Foxx, basketball sensation LeBron James and Maroon 5 frontman Adam Levine are also expected to attend the fight.

The bout is particularly eagerly anticipated because it will see undefeated boxer Mayweather taken on an Ultimate Fighting Championship (UFC) star in McGregor, in what will be the Irishman's first fight as a professional boxer.