The main event for UFC 311 has been dramatically changed just 24 hours before Saturday's card in California.
Lightweight champion Islam Makhachev was due to defend his title against Armenia's Arman Tsarukyan.
But Tsarukyan has now pulled out of the title bout due to a back injury.
The UFC have wasted little time in finding a replacement, with Brazil's Renato Moicano stepping in to challenge Makhachev for lightweight gold.
UFC president Dana White announced the news on Friday in a social media video. White said: 'Around 1am we received a call from Arman Tsarukyan who informed us that he was experiencing significant back pain. Due to the injury, he feels like he is not healthy enough to compete.'
More to follow...