"It's so good to see famous people again," David Letterman declared as he took the stage as a guest on Tuesday's Jimmy Kimmel Live.
The 70-year-old comedian's appearance on JKL -- which is filming all week in Brooklyn, New York -- marked the first time he's been on late-night TV since he retired over two years ago as the host of CBS' The Late Show.
"It feels so good to be out of the house, ladies and gentlemen!" Letterman joked before calling out Paul Shaffer, the former band leader of The Late Show, for also making an appearance on Kimmel's program. "Paul, you work here now?"
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Letterman sarcastically revealed what he misses most about being on TV every night. "I miss wearing makeup," he mused, later adding, "I'm profiling through, 'Was I fired or did I retire?'"
Kimmel -- who wore a tie that Letterman gifted him when he left The Late Show -- insisted, "You retired! There was a whole thing."
Letterman then took a walk down memory lane and recalled the time he gifted Conan O'Brien with a horse, which didn't go over too well.
The intention behind the present was that O'Brien would bring the horse out on his show and it would "take a dump" on the stage, an idea that Letterman found "hilarious."
However, the former host said a few days later, he learned something went "terribly wrong."
"I get this warm, lovely letter that says, 'My wife loves the horse, and she's going to keep the horse because she an equestrian'" Letterman reminisced. "Now I'm screwed because I was counting on him returning the horse and I get my money back."
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Further defending the gift, he exclaimed, "It was joke! Take a dump on the stage, load him up, get him back!"
O'Brien has apparently changed his mind about the horse since his "warm letter."
"From what people are talking about, Conan will just not shut up about the horse. The horse has gone crazy, maybe its from being around Conan all day," Letterman quipped. "Of course he's unridable, all he had to do was take a dump on the stage."
For 33 years, Letterman fans got to watch jokes such as these when he was a late-night television host, first getting his start on NBC's Late Night before going on to host The Late Show.
On May 20, 2015, over 13 million people watched Letterman host his final episode of The Late Show. Here's a look at some of the highlights from the memorable evening: