US Supreme Court nominee Brett Kavanaugh was reportedly involved in a bar fight after a UB40 concert in 1985.
The judge is said to have thrown ice at someone who he thought resembled the English reggae band’s lead singer Ali Campbell.
The altercation allegedly happened three years after Mr Kavanaugh is accused of sexually assaulting Christine Blasey Ford at a party.
She is one of three women to make sexual misconduct allegations against the judge.
Mr Kavanaugh passionately denied the accusations at a Senate committee hearing on Thursday, and challenged suggestions he had a drinking problem at the time.
He said: “Sometimes I had too many beers, sometimes others did.
“But I did not drink beer to the point of blacking out and I never sexually assaulted anyone.”
The New York Times has reported that Mr Kavanaugh was questioned but not charged by police after the 1985 bar fight in New Haven, Connecticut.
The paper has published police reports but personal information has been redacted.
Charles Ludington, who was a witness, said a man resembling UB40’s lead singer had asked Mr Kavanaugh and his friend Chris Dudley to stop looking at him and used an expletive.
Mr Kavanaugh allegedly threw ice at him.
Mr Dudley, a Yale basketball player, is then said to have grabbed his beer and “smashed into in the head of the guy, who by now had Brett in an embrace”.
Mr Ludington made the allegations in a statement published on Sunday.
He said that after the attack he “tried to pull Chris back, and a bunch of other guys tried to pull the other guy back”.
Mr Ludington added: “I don’t know what Brett was doing in the melee, but there was blood, there was glass, there was beer and there was some shouting, and the police showed up.”
The North Carolina State University professor has challenged Mr Kavanaugh’s testimony that he was not a heavy drinker, and indicated that the judge was “belligerent and aggressive” when he drank.
Mr Ludington told reporters: “I can unequivocally say that in denying the possibility that he ever blacked out from drinking and in downplaying the degree and frequency of his drinking, Brett has not told the truth.”
The altercation is said to have happened in a bar called Demery’s that closed in 1994.
US President Donald Trump has defended his pick for the Supreme Court but admitted that the appeals court judge has had a “bit of difficulty” with alcohol.
Mr Dudley, a Republican nominee for governor of Oregon in 2010, has spoken out in defence of Mr Kavanaugh’s Supreme Court nomination.
He has also disputed reports the judge drank excessively.
US media has reported that the FBI has begun interviewing Mark Judge, Kavanaugh’s former best friend and a key figure in the misconduct allegations levelled by Ms Ford.
Mr Judge’s interview started but “has not been completed”, his attorney said in a statement quoted by Fox News.
In last week’s hearing, Ms Blasey Ford said Mr Judge witnessed Mr Kavanaugh’s alleged assault and jumped on top of them as it happened, sending all three tumbling and allowing her to escape.
Meanwhile, Mr Trump said the White House would not restrict the new FBI probe requested by senators before they take a final vote on Mr Kavanaugh.
Harvard University’s student paper has reported that Mr Kavanaugh will not return to teach law in January.