On Tuesday, the three late night personalities teamed up for a nearly unprecedented cross-network sketch that served as the cold open for both Fallon's Tonight Show, on NBC, and Colbert's Late Show, on CBS, at the same time.
One day after Trump slammed the three hosts during a campaign rally supporting South Carolina Gov. Henry McMaster, the trio appropriated the insults the president hurled to mock him in return.
The bit begins with Colbert typing up his monologue on a computer when he gets a video call from Fallon, who cheerily greets him, "Hey lowlife!"
"Hey lost soul," Colbert replies, beaming. "What are you up to?"
"Mostly whimpering," Fallon admits.
"Be a man," Colbert shoots back, calling back to Trump's tweets earlier this week when he first insulted the Tonight Show host.
"I'll try," Fallon says, shrugging. "What are you up to?"
"I’m busy having no talent!" Colbert states, proudly. As the pair chat, Fallon tells Colbert about the president mocking the two of them during his rally, calling them "no talent, lowlife lost souls."
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Watch Alec Baldwin and Jimmy Fallon Test Out Their Best Donald Trump Impressions
"Well that's not right," Colbert says, confused. "That's Conan."
Colbert then brings the redheaded host into the video chat, where they catch him mid-shave. O'Brien -- whose TBS talk show, Conan, is on hiatus for this week -- jokingly says he didn't realize that Trump had even become president, but states that they should just "give him time," and implores them to be respectful and polite.
"Remember, be civil!" O'Brien insists. "If we're not careful, this thing could start to get ugly."
After hanging up on O'Brien as he starts to shave his chest hair, Fallon asked Colbert if they're still on for lunch, and the pair both agree on dining at the Red Hen -- the Lexington, Virginia restaurant that recently made headlines when they refused to serve White House Press Secretary Sarah Huckabee Sanders, and were subsequently the targets of Trump's ire on Twitter.
The typically non-political host made a point of going after the president following their twitter spat, which culminated in Fallon making a donation to the non-profit group RAICES, a Texas-based immigration services group, in Trump's name.