Conor McGregor has been fined €1,000 (£860) for punching a man in a Dublin pub in April.
The former two-weight UFC champion entered a guilty plea at Dublin District Court on Friday after his initial hearing in the morning was adjourned.
The court was then shown CCTV footage of the incident in which McGregor offered the victim Des Keogh a shot of his Proper Twelve whiskey.
The victim declined and McGregor slammed a shot glass down in front of him before punching him on the left side of his face.
McGregor's solicitor told the court that the fighter apologised to Mr. Keogh who accepted his apology.
The court also heard that McGregor had 18 previous convictions, including several for speeding and one for a prior assault in 2009, and that his victim had already been compensated.
Addressing the court, McGregor said: "I assure you nothing of this nature will happen again regarding me."
McGregor, who is worth more than £100million, has one month to pay the fine after the judge said a jail term would be inapppropriate.
The Dubliner has constantly flirted with controversy since he was last in action in the UFC.
McGregor has not fought since he was choked out by lightweight champion Khabib Nurmagomedov last October but plans to return to the Octagon on January 18.
Donald Cerrone is the leading candidate to take on McGregor with the former champion then planning to fight again in April against the winner of Nate Diaz vs Jorge Masvidal and in September against the winner of Nurmagomedov's planned title defence against Tony Ferguson.
McGregor, who was also involved in an altercation with a fan in Miami earlier this year, admitted in an interview with ESPN in August that he gone astray.
"That man deserved to enjoy his time in the pub without it having to end the way it did.
"Although it was five months ago and I made amends back then, it doesn't matter.
"I was in the wrong, I must come here and take accountability and responsibility.
"I owe it to the people who have been supporting me, my mother, my father, my family. I owe it to the people who trained me in martial arts. That is not who I am, that's not the reason I got into martial arts.
"I got into it to defend against that scenario. To see that, it is like a dagger into my heart.
"I am just hear to own up to that and move on and face what is coming.
"What happened is hazy for me and it was many months ago and I am taking steps to ensure it doesn't happen again.
"What happens next I will deal with, I will face.
"I deserve to be called out on my behaviour because it is unacceptable. To see my fans disappointed in me hurts me to the soul more than you can know."
