Kubrat Pulev has been fined and banned for grabbing a female broadcaster's face and kissing her on the lips during a post-fight interview.
Pulev, a heavyweight contender known as "The Cobra," was also ordered during a commission hearing to attend sexual harassment prevention classes and pay a $2,500 (£2,000) fine before he can fight again in the state of California in July.
Pulev, who has only one loss in 27 fights, grabbed Jennifer Ravalo's face and kissed her in the middle of a live interview moments after knocking out Romania's Bogdan Dinu in the seventh round of a March fight in Costa Mesa, California.
One of Bulgaria's most popular sportsmen, Pulev apologised for his actions during the hearing as his girlfriend, the Bulgarian pop star Andrea, sat behind him, wearing dark glasses.
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Attorneys for Pulev said that the fighter had got caught up in the moment following his big win and "didn't have his wits about him" when he kissed the reporter.
Pulev and his lawyers argued in the hearing that Ravalo did not appear to be very upset about the incident because she joined the boxer and his team at a post-match celebration later that night.
But Ravalo said in tearful testimony that Pulev also grabbed her buttocks off-camera following the interview, leaving her feeling humiliated, and has not apologized in the two months since.
"I did not want him to kiss me," Ravalo said.
