David Letterman celebrates 30 years in late night

With three decades on late night TV under his belt, David Letterman opted to celebrate the occasion by bringing on an old friend: Howard Stern.

The New York Times noted ahead of Wednesday's edition of "Late Show" that the host was going to keep it casual. After a few jokes in his opening monologue - what keeps him going night after night is "Lipitor and vodka," it turns out - his staff took the opportunity to roast the veteran host during the Top 10.

(Among the top things his staff wanted to say to Letterman on his 30th anniversary included, "You're incompetent," and, "I stopped watching in 1992.")

When Stern joined, Letterman brought out the photo of his first appearance on "Late Night" in 1984 - and pointed out that he's gotten so much better looking over the years.

"Back then," Stern told him, "the fact that you asked me to be on a national TV show was mind-blowing to me."

And look at them now: Years later, Stern told Letterman, he's still loyal to him.

"I'm going to work for NBC on 'America's Got Talent' [as a judge] and they sat down with me and had a big meeting about promoting the show. They said, 'Listen, you'll do the 'Today' show, and of course you'll do Jay Leno. And I shot 'em a look and I said, 'You know I'm a Letterman guy?' I'm probably the only idiot in show business who picks sides in late night wars, but I'm true to it."