Conway allegedly punched a man at the exclusive inaugural Liberty Ball, just hours after Trump was sworn in as president.
Witnesses said Trump's right-hand woman intervened when two men, who appeared to be in her entourage, got into a fistfight at the invite-only bash at the Washington Convention Centre on Friday, The New York Post reports.
Conway, currently under fire for her "alternative facts" comment, was seen pushing the men apart before appearing to throw some "mean punches" at one of the brawlers.
Fox Business Network correspondent Charlie Gasparino, who claimed to have witnessed the incident, wrote on his Facebook page: "Inside the ball we see a fight between two guys in tuxes and then suddenly out of nowhere came Trump adviser Kellyanne Conway who began throwing some mean punches at one of the guys. Whole thing lasted a few mins no one was hurt except maybe the dude she smacked."
The melee allegedly kicked off near a VIP area at the ball shortly after Trump and First Lady Melania completed their first dance and left, and it looked like it involved friends or family of Conway.