Mayweather made the announcement on Twitter, confirming that the 40-year-old will end a 23-month retirement to face McGregor in a boxing match on Aug. 26.
Specific terms of the bout were not revealed, such as number of rounds, weight class or location. The event is thought to be held at either MGM Grand Garden Arena in Las Vegas or the T-Mobile Arena, also in Las Vegas.
The Nevada State Athletic Commission approved a request submitted by Mayweather Promotions to host a boxing event on Aug. 26 at the MGM Grand Garden Arena, ESPN reported earlier on Wednesday.
The news came on the heels of Mayweather Promotions reportedly planning to retract the request for the date before informing Nevada State Athletic Commission officials late Tuesday that they were ready to proceed.
"I got a call (Tuesday) night from Mayweather Promotions that they wanted to be put back on the agenda, so I put them back on the agenda," Bob Bennett, executive director of the Nevada State Athletic Commission, told ESPN. "They pulled the request but then decided to put it back on."
Neither fighter has competed this year. Mayweather (49-0, 26 KOs) retired from professional boxing after defeating Andre Berto in September 2015 while McGregor (21-3) bested Eddie Alvarez at UFC 205 in November 2016.