Fox News host Bill O’Reilly landed on the “Late Show” with David Letterman for his first big, non-Fox News TV interview since he sustained a round of well-sourced allegations that he’d spread falsehoods or even fabricated self-aggrandizing stories about his reportorial past in Argentina, El Salvador, Northern Ireland and elsewhere. And boy was it ever a great choice.

The genial late-night host not only provided some nice promotion for the National Geographic Channel’s March 29 premiere of “Killing Jesus” — an adaptation of O’Reilly’s best-selling book by the same title — but also he  exonerated the King of Cable News. He did it with style and efficacy, too.

After talking about “Killing Jesus” and presidential politics, Letterman steered the discussion toward Brian Williams, the truth-challenged suspended anchor of NBC Nightly News. On that topic, O’Reilly offered some sage thoughts that managed to frame the millionaire famous NBC guy and himself, the millionaire famous Fox News guy, as victims: “From the beginning I’ve said that, you know, we have a sport in the United States called ‘Let’s destroy the famous person,’ and that’s what happened to him,” said O’Reilly, who noted this was his 16th time on the program. Both guys agreed that NBC News should bring Williams back.

The transition into O’Reilly’s troubles was an easy one for Letterman: “When this came up, then people started saying, well, Bill O’Reilly himself may have said himself things that were exaggerated or untrue, and they had to go back like 30 years,” said Letterman in a deft move to belittle, undermine, cheap-shot and poke holes in the anti-O’Reilly reports before even discussing their merits. (Total full disclosure: The story that kicked off O’Reilly’s troubles came from Mother Jones, where the Erik Wemple Blog’s wife is a staff writer).

O’Reilly corrected Letterman: Those punks had to go back 38 years. Indeed, journalist Jefferson Morley and Media Matters raised questions about how O’Reilly recalled being at the front door of a Florida house in March 1977 when a figure in the investigation of the JFK assassination died of a shotgun blast inside.

If O’Reilly’s indiscretions were time-stamped with more recent dates, what would be the difference between his situation and that of Williams? asked Letterman. “Only if I did something that wasn’t true,” O’Reilly responded. “What I did was accurate…So we had a controversy there. We put forth what my side was, they put forth what their side was, folks decided and it worked out okay for me. I got even more viewers.”

Asked whether he’d ever “fibbed” on air, O’Reilly said he wasn’t aware of any such incidents.

Letterman appears to have a genuine soft spot for un-truthy TV news guys. His grand exoneration of Brian Williams, honest to God, consisted of averring that the NBC News anchor never said the following: ” ‘Ladies and gentlemen, I’ve seen martians. Run for your lives…Go to your basements immediately, the martians are here.’ Now, he didn’t do that.” The takeaway: Millionaire entertainers who help one another promote their shows look out for each other.