But seriously, folks ... Mitt Romney is a really funny guy.

“He’s got a spectacular sense of humor,” senior Romney adviser Ron Kaufman insisted at Tuesday morning’s Politico Playbook Breakfast in Tampa, where Republicans geared up to formally nominate the straight-laced Mormon at their national convention this week. “He has Northeast humor,” Kaufman said about the former Massachusetts governor. “Dry humor. Jerry Seinfeld.”

Romney, who raised eyebrows recently at a rally in his native state of Michigan with his “joke” about not needing a birth certificate—a none-too-veiled reference to birtherism and President Obama—has yet to demonstrate his comedy chops for the public. And Kaufman, under questioning from Politico’s Mike Allen, declined to provide examples of his candidate’s hilarity.

But he said that once, during the 2002 Winter Olympics in Utah that Romney ran, “we spent an hour in the car from Park City talking about who’s the better prankster.”

Has Romney ever played a prank on Kaufman?

“Yes, but I’m not going to tell you,” the adviser said. “We play some good tricks on him ... We’re into short-sheeting ... We’ll put an event on the schedule, and there’s actually no event.”

At which point the breakfasters erupted in uncontrollable, explosive, side-splitting laughter.

Or maybe they didn’t.