Watch David Letterman Return to Late Night TV on 'Kimmel'

Former 'Late Show' host talks Conan O'Brien horse story, reunites with Paul Shaffer in first post-retirement late-night appearance

Two years after retiring from 'The Late Show,' David Letterman returned to late night television Tuesday when he visited 'Jimmy Kimmel Live.'

Two years after retiring from The Late Show, David Letterman returned to late night television Tuesday when he visited Jimmy Kimmel Live. In addition to a 15-minute interview, Letterman also reunited with his former bandleader Paul Shaffer, who's serving the same role this week while Jimmy Kimmel's show films in Brooklyn.

"Paul, you didn't tell me you work here now," Letterman yelled over to Shaffer upon sitting down at the Brooklyn Academy of Music.

Over the course of the interview, Letterman discussed his upcoming Mark Twain Prize for American Humor ceremony, what he misses about late night television, his in-the-works Netflix show and that recent rumor that he sent Conan O'Brien a horse.

According to Letterman, he did send O'Brien a horse as a "fucking show business gift" when O'Brien took the Tonight Show job, but the horse – a rental used for Hollywood shoots – was only meant to be a prank: Letterman envisioned it going on The Tonight Show, "taking a dump" and then heading back to the farm, at which point Letterman would get his deposit back.

"Two or three days later, I realize things have gone terribly wrong," Letterman told Kimmel. O'Brien's wife, an equestrian, decided to keep the horse. However, the horse turned out to be "unrideable."

Earlier this month, O'Brien appeared on Stephen Colbert's Late Show to complain about the unruly horse.

"It was a joke: Take a dump on the stage, load him up, send him back," Letterman said. "Conan will not shut up about the horse. The horse has gone crazy. Maybe it's from being around Conan all day… So now he's complaining, and there may be litigation, and maybe I'll get a call from PETA. And [the horse] apparently broke into Conan's mansion."

Despite the incident, Letterman had nothing but praise for all the current late-night hosts. "For the purpose of this conversation I have nothing but the highest regard for all of the talk show men and women – even Jimmy Fallon. I'll include him," Letterman said.

Letterman dodged questions about his upcoming Netflix show, admitting only that Howard Stern would be a guest on one episode. "The thing I like about this, [Stern] seems to be nervous about this, and anytime you can get Howard nervous I think you've accomplished something," Letterman said.

When asked whether he misses late night, Letterman hesitated before saying, "No, I don't. I miss wearing makeup."

"I am a bit of a different person," Letterman says of his post late-night life. "And I mean, thank God. Because the great struggle in life is to be better each and every day, and if you take a look around the horizon of humanity, my god, is there anything we can do big or small to make the life of just one person a little bit better, and that's no small accomplishment."