Bill O'Reilly Bill O'Reilly

David Letterman wasted no time launching jabs at Bill O'Reilly on The Late Show.

"I think of you as a goon," Letterman quipped, barely a minute into the Tuesday interview with his frequent sparring partner. (Watch part of the interview here)

Holding up O'Reilly's book, A Bold Fresh Piece of Humanity, which is emblazoned with a photo of young O'Reilly, Letterman continued, "I look at that and I see this sweet, adorable kid... I have a sweet adorable kid and I wonder, 'What if he too becomes a goon?'"

Letterman kicked things off by discussing O'Reilly's various journalism gigs that led to his ascension at Fox News with The O'Reilly Factor.

"So when you say 'working your way up,' does that really apply to Fox?" Letterman asked.

Talk turned to Rush Limbaugh, whom the late-night host implied may now be the head of the GOP. O'Reilly believes conservatives fear the influential radio show host and that they don't want to "offend the man."

"It just seems to me that he's too smart to believe what he's saying. And I feel the same way about you," Letterman said. "You're too smart to believe what you say."

Letterman couldn't let O'Reilly go without mentioning his recently announced boycott of Sean Penn's films because of the Oscar winner's political beliefs. "It's gonna be on your conscience when you put him out of work."

When it was all said and done, the drilling wasn't as painful as expected. "OK, I think we're done here. I'd like to see you back here in six months for a cleaning," Letterman said.