Earlier in the evening Lange, 49, had performed at Carolines as he recovers from recent surgery for a chest infection following years of drug abuse.
Star comics Judah Freidlander, Dave Attel, Aziz Ansari, were all also at The Cellar.
But the fun atmosphere quickly turned sour when Stewart, 54, stood up for a surprise performance but not before he got into a swearing match with Opie & Anthony’s Cumia.
When Cumia, 56, went to shake the former talk show host’s hand, he was met with Stewart firing expletives at him.
“I wouldn’t shake your f***** hand if you paid me,” Stewart roared.
“You’re the lowest scum on this Earth!”
Cumia, being held back by his girlfriend and former Howard Stern alum Steve Grillo, yelled: “I wouldn’t expect less from you, you phony, f***** Hollywood ass****!”
According to an eyewitness the two men almost came to blows as they traded insults with one another before Cumia left the venue and Stewart took to the stage.
Cumia tweeted afterwards: “I may have just gotten into a lil discussion with Jon Stewart at The Cellar. We are not fans of each other."
It’s understood that the two men have very different views and this could have sparked their argument.
Cumia is known to be a Republican leaning while Stewart is a hard core liberal.
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