Fox Business Network senior correspondent Charles Gasparino said it happened after two tuxedo-clad men got into an argument inside the exclusive, invite-only Liberty Ball Friday night.
"Suddenly out of nowhere came Trump adviser Kellyanne Conway who began throwing some mean punches at one of the guys," Gasparino wrote on Facebook Monday.
"Now I know why Trump hired her," he added.
While it is unknown what triggered the alleged fight, Conway has not commented on the matter.
Gasparino wrote: “Whole thing lasted a few mins no one was hurt except maybe the dude she smacked."
Conway revealed that she is now receiving Secret Service protection after becoming the president’s most visible and outspoken adviser.
On Monday night, she told Sean Hannity on his Fox News show: “Because of what the press is doing now to me, I have Secret Service protection. We have packages delivered to my house with white substances. That is a shame.”