Despite his success in the UFC mixed martial arts promotion, Conor McGregor maintained an interest in boxing competitively again, and entertained the idea of a “money fight” with Floyd Mayweather Jr. Mayweather reportedly talked to Freddie Roach to train McGregor for the fight in case it would happen. UFC president Dana White dismissed the rumors of a fight with Mayweather on The Dan Patrick Show, stating that Mayweather would have to contact him since McGregor was under contract with the UFC. White even went as far as stating, “Here’s what I think the chances are (of the fight happening): About the same of me being the backup quarterback for Brady on Sunday,” referring to Super Bowl LI. In January 2017, it was reported that the two parties had entered an “exploratory phase” in negotiating a potential match between Mayweather and McGregor. On The Herd with Colin Cowherd, White openly offered to pay Mayweather $25 million to hold the proposed bout during a UFC event. He also predicted that pay-per-view viewership of the hypothetical bout could possibly rival Mayweather vs. Pacquiao.
On March 7, 2017, Mayweather called upon McGregor to “sign the paper” and “make it happen”, arguing that “if Conor McGregor really wants this fight to happen, stop blowing smoke up everybody’s ass.”On March 10, 2017, Mayweather stated that only a fight with McGregor would make him come out of retirement. On March 16, 2017, Dana White backpedaled on his stance against a Mayweather-McGregor bout and said that he would not deprive McGregor in making a massive payday. On May 18, 2017, McGregor reportedly agreed to all of Mayweather’s updated terms and signed the contract.
IBF super featherweight champion Gervonta Davis will participate in a co-main event. An international press tour was held from July 11–14.
On July 19, 2017, additional undercard details were released. To date, three names have been confirmed on the undercard, including British amateur boxer Savannah Marshall who signed up earlier in the year with Mayweather Promotions and Badou Jack who will be stepping up to fight at light heavyweight.
On a July 24, 2017 episode of the Pardon My Take podcast, hosted by BigCat and PFTCommenter, former heavyweight boxing champion Mike Tyson predicted McGregor “is going to get killed boxing.”
A mural was painted in McGregor’s Dublin training facility, Straight Blast Gym, depicting McGregor hitting Mayweather with a left-handed punch.