It started when MacFarlane went after Stewart on Family Guy, making fun of him for working through a live show during the Writers Guild strike in 2007, even though Stewart's writers were on strike.

Apparently Stewart didn't take the jab too lightly, got ahold of MacFarlane's number and furiously dialed him up.

"It was an angry call, and suffice it to say he's a phenomenally good debater," MacFarlane said. "If you'd been keeping score, I would have lost roundly."

When Morgan asks if he groveled or stood his ground like a man, MacFarlane says he did try, but was taken aback by the absurdness of the whole thing.

"I was kind of in shock more than anything else, it was kind of an odd Hollywood moment," he explained. "I mean I was a huge fan of his show and here I was getting this phone call, this really, really angry phone call.