Jose Aldo has been forced to pull out of the UFC featherweight title fight with Dubliner Conor McGregor.
'The Notorious' McGregor will now face Chad Mendes for an interim title.
Brazilian Aldo announced his intention to pull out of the Las Vegas fight after he succumbed to a rib injury he suffered in sparring, despite being passed fit by doctors.
Following initial rumours of the fight being cancelled, Aldo attempted to recover in time to still compete on the pay-per-view card, but was forced to pull out.
McGregor reacted to the news in true McGregor fashion and commented: "If a man is scared for his life, we can not force him to step inside and fight me."
McGregor took to Twitter following the announcement and said: "They can run. But they can't hide."
UFC president Dana White said it was disappointing news for fans.
"Aldo's rib is too painful and he will not be fighting," he said.
"Chad Mendes will fight Conor McGregor for the interim belt. It's (Aldo's) decision. I don't feel great about it.
"Doctors have cleared him to fight - it's a bruise - but he still pulled out," he added.
"The belt should be taken from him and we will contest for the interim belt or, in my opinion, the real belt," Conor said.
Meanwhile, after the huge success of the UFC event in Dublin in July 2014, UFC has announced a new show for this October.
No fights have been confirmed or lined up for the night, but given that 'The Notorious' will still be in action against Chad Mendes later this month, it is unlikely that he will feature.
However, other Irish fighters in the UFC such as Cathal Pendred, Neil Seery, Paddy Holohan and Joseph Duffy are all likely to be involved.