At the end of the monologue on NBC's "Late Night With Jimmy Fallon," the New York-based host showed viewers a photo of the present he had sent to Ferguson - a "beautiful, top-notch Christmas sweater" (in Fallon's words) accented with both his face and Ferguson's against a Christmas ornament.
"He's over at CBS in L.A. and I know how cold it gets at night there," Fallon explained.
What had Ferguson given in return? Under his desk, Fallon found a large gift box containing two kittens named Regis and Kelly.
At almost the same moment on CBS' "Late Late Show with Craig Ferguson," its host was eagerly unwrapping the box that contained the sweater from Fallon.
"Oh, I know you're like, 'Craig, you're crazy, he's your direct competitor, you can't say how great Jimmy is,"' cracked Ferguson, "but everybody knows it: Jimmy is awesome. ... Everybody knows Jimmy Fallon is the best knitter in show business."
Before launching into another of his one-man dialogues, Ferguson alerted viewers to the gift he had sent to Fallon.
"He should get it tonight. 'You mean on his show, which is in direct competition with yours, Craig?' Yes. 'Craig, you're confusing us, what should we do?' I don't know. I'm not your parents!"
The transcontinental, cross-network gift swap was the latest comic stunt bonding these rivals in the 12:35 a.m. (Eastern) hour.
In the past, they engaged in a food fight with spaghetti and waved at each other with giant novelty Mickey Mouse hands.
"I can't think of someone I'd rather be against this time of night," said Ferguson on Thursday with a naughty look. "I love being against you after midnight, Jimmy!"
So there's peace and goodwill among these men.
But Ferguson added, "For all those media hacks that like to poke the hornet's nest and say there's a late-night war - go right ahead!"