Conor McGregor's comeback fight has been cancelled due to injury just two weeks before he was due to face Michael Chandler in Las Vegas.
The Irish mixed martial arts star, 35, has been out of action since breaking his leg in a July 2021 defeat to Dustin Poirier but was scheduled to top the bill at UFC 303 on 29 June.
However, his bout has now been pulled due to an unspecified problem.
"Conor McGregor is out of 303 versus Michael Chandler with an injury," UFC chief executive Dana White announced in a video posted on X.
Light heavyweight champion Alex Pereira will defend his belt against Jiri Prochazka in the new main event.
McGregor is one of the biggest stars in the history of the hugely successful Ultimate Fighting Championship (UFC) mixed martial arts circuit, formerly holding the featherweight and lightweight titles.
He made headlines in November when he sent a series of social media posts during unrest in Ireland, criticising the government's immigration policy.