Boxing legend Floyd Mayweather will fight UFC lightweight champion Conor McGregor in Las Vegas on Aug. 26.

The 40-year-old Mayweather, who retired with an undefeated 49-0 record in 2015, made the announcement on  Instagram Wednesday.

“It’s official,” Mayweather said on his Instagram account next to a video poster of both fighters.

Mayweather is one of the best pay-per-view draws the sport has ever seen as Forbes listed him as the highest-paid athlete in the world in 2014 and again in 2015.

Mayweather will fight at the relatively advanced age of 41 in a bout that McGregor has been pushing for months. It finally came together over the last few days, and Nevada boxing officials on Wednesday approved the date for a Mayweather Promotions bout.

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Though Las Vegas oddsmakers have made Mayweather a heavy 10-1 favourite, the thought of the fight has excited many in the MMA world. It has also intrigued some in boxing, though most dismiss McGregor’s chances against one of the greatest defensive fighters in history.

Even if the actual bout may not shape up as a great matchup, the run-up to the fight will. Both fighters are noted for their ability to sell their fights, and both have exchanged trash talk and more to promote their bouts.

The fight will be televised on pay-per-view on Showtime and would likely gross tens-of-millions of dollars. It comes less than a month before Gennady Golovkin and Canelo Alvarez meet in a highly anticipated fight that could rival it for pay-per-view buys.

  • With files from Associated Press