The highly anticipated rematch between Jon Jones and Daniel Cormier will not happen.
Jones has been removed from the UFC 200 headline bout following a potential anti-doping violation.
The new headliner for Saturday's event in Las Vegas will be Brock Lesnar against Mark Hunt.
UFC president Dana White made the announcement on Wednesday, calling it "super disappointing" and "devastating" for Cormier.
"This sucks. I don't know what to say. It's unfortunate," said White, who added Jones could get a two-year suspension for the failed out-of-competition test on June 16.
A failed test would be the second in three scheduled fights for Jones and is the latest in a string of controversial incidents.
Jones beat Cormier at UFC 182 on January, 2015, in a unanimous decision.
The victory gave Jones the UFC light heavyweight championship, but he was stripped of that title three months later following his arrest on felony hit-and-run charges.
He was reinstated by UFC in October, and a rematch with Cormier was scheduled for April 23, 2016, at UFC 197, but Cormier had to withdraw because of a foot injury.
UFC will review the case before any sanctions are imposed, but there was not enough time before Saturday's event.