Wyclef Jean -- I'm Singing the Haitian National Anthem ... at the Mayweather/Berto Fight!

The Floyd Mayweather/Andre Berto fight is getting a little taste of the Fugees ... rapper Wyclef Jean will perform the Haitian national anthem before the fighters throw down.

According to our sources, Berto (whose parents emigrated from Haiti) had his camp reach out to Wyclef's people, asking him perform "La Dessalinienne" at the big fight this weekend.

We're told Clef is on his way to Vegas.

No word yet on what big star will be performing "The Star-Spangled Banner," but we know Britney Spears is in town ...