Ireland's McGregor, a former two-weight champion and still one of UFC's most famous and bankable fighters, hasn't fought since suffering a broken leg in a loss to Dustin Poirier on July 10, 2021.
July's return at UFC 329 will be a rematch of his second UFC fight, in August of 2013, when McGregor beat Holloway in Boston despite suffering a torn knee ligament during the bout.
The 37-year-old Dubliner had withdrawn from a planned comeback fight in June of 2024 with a toe injury.
McGregor has dealt with multiple issues outside the Octagon.
In 2024, he was found liable and ordered to pay around $250,000 damages to a woman who accused him of rape in Ireland.
Then this past December, a woman who accused McGregor of sexually assaulting her at an NBA game in Miami dropped her civil lawsuit against him, authorities having already declined to pursue criminal charges.
A month earlier, McGregor was suspended for 18 months after missing three drug tests in 12 months, escaping a longer ban after Combat Sports Anti-Doping said he cooperated with their investigation into the missed tests.
UFC announced the bout during the first MMA promotion by YouTuber-turned-boxer Jake Paul's Most Valuable Promotions outfit, a card in Los Angeles highlighted by Ronda Rousey's return against Gina Carano.