Conor McGregor has been slapped with a multi-million-pound lawsuit days before he returns to the cage.
The Irishman is being sued by a woman over events that allegedly took place in 2018.
The nature of the allegations cannot be disclosed and McGregor, 32, has denied all wrongdoing.
A separate, smaller claim has been filed at the High Court in Dublin by the woman's mother.
The allegations were previously investigated by Irish police but no action was taken.
In a statement, Mr McGregor’s spokesperson Karen J Kessler said: “After an exhaustive investigation conducted by the Gardaí which, in addition to interviews of the plaintiff, included interviewing numerous sources, obtaining witnesses' statements, examining closed circuit footage and the cooperation of Conor McGregor, these allegations were categorically rejected.
“The plaintiff knows the facts contradict the assertions in this lawsuit. Mr McGregor will dispute any claims and is confident that justice will prevail.”
McGregor is currently in Abu Dhabi preparing to face Dustin Poirier on Sunday morning.
The rivals first met in 2014 when McGregor needed less than two minutes to win by stoppage.
He went on to win first the featherweight and then the lightweight title before taking on Floyd Mayweather in the second-richest fight of all time.
He returned to the UFC in 2018 when he was choked out by bitter rival Khabib Nurmagomedov before he took a 15-month hiatus.
McGregor returned to action 12 months ago when he stopped Donald Cerrone inside 40 seconds.
He hopes victory over Poirier will propel him to another title shot, either against champion Nurmagomedov or, if the Dagestan native retires, the next available contender.