By TMZ Sports
It's on ... WBC/WBA welterweight champion Floyd Mayweather (48-0, 26KOs) is officially set to square off with Andre Berto in September ... TMZ Sports has confirmed.
The two have been in talks for weeks ... but now we're told from both camps that it's a done deal and the two will fight at the MGM Grand in Las Vegas on September 12th.
We spoke with Berto who tells us, "It's a pleasure and honor to be in this position and I'm looking forward to capitalizing on every moment of it".
As we previously reported, there's some bad blood between the two -- with Berto claiming Mayweather had been crank calling his phone ... and he believes it was all over a woman.
Mayweather has fought on a pay-per-view platform for the last decade. The fight with Berto is expected to take place on network television, with CBS airing the match.
Story developing ...