Floyd Mayweather Jr. finally confirmed that he will fight Andre Berto on Sept. 12 at the MGM Grand in Las Vegas.

The fight, Mayweather’s last in his six-fight deal with Showtime, will be on Showtime Pay-Per-View.

Mayweather, 38, made the confirmation on Instagram, posting an image of him and Berto with the words: “Mayweather, Berto, live on Showtime PPV, September 12, 2015, MGM Grand Garden Arena.”

Showtime Sports confirmed the news on its Twitter account.

Mayweather (48-0, 26 knockouts) has said this will be his final fight.

Berto was rumored to be Mayweather’s choice for several weeks even though many fans have been critical of the notion.

In he current RingTV.com poll, asking readers who they would want Mayweather to fight, Berto is 10th among 11 potential opponents. Middleweight champ Gennady Golovkin is the runaway leader in the poll.

Berto (20-3, 23 KOs) has beaten Steve Upsher Chambers and Josesito Lopez in his last two fights but is only 3-3 in his last six, leading some to wonder about his qualifications to face Mayweather.

Another rumor was that the fight might be televised on free TV, on CBS, as payback for his disappointing fight against Manny Pacquiao on May 2. Fans paid as much as $100 for the boring fight.

Mayweather will attempt against Berto to equal Rocky Marciano’s record of 49-0, which which the late heavyweight champ retired.