Obama became the first sitting president to appear on Letterman’s show on Sept. 21, 2009, and also appeared on the show Sept. 18, 2012 and most recently on May 4.
“Dave, let me just say this,” he said in his last appearance, “and I mean this sincerely, and I know I speak for Michelle — she probably had a chance to say it herself — you know, we’ve grown up with you.
“The country I think has, you know, after a tough day at the office or coming home from work, knowing you’ve been there to give us a little bit of joy, a little bit of laughter, it has meant so much, and you’re part of all of us … you’ve given us a great gift, and we love you,” he added.
“I could help you through those dark times,” she said.
10 of David Letterman's Most Memorable Guests (Photos)
Bill Murray was Letterman's first guest on "Late Night," and the actor always makes a splash when he returns, including fabulous entrances as Liberace and Peter Pan.
Dave wasn't always safe behind his desk, as Crispin Glover proved when he showed off his kicking ability for the late-night host.
Madonna stopped by for a profanity-filled visit to the "Late Show" in 1994, where she openly discussed her sex life.
Howard Stern has stopped by numerous times to converse with his fellow talk-show host. Their lively conversations always make for entertaining TV.
Oprah stopped by "Late Night" in 2005 to put an end to her and Letterman's alleged "feud."
Drew Barrymore showed off her moves on Dave's desk -- and, for an encore, flashed the host.
What would later be revealed as an elaborate method acting job, Joaquin Phoenix's bizarre appearance in 2009 confused not only Letterman, but most of America as well.
After years of jokes when she was the first lady, Letterman welcomed Hillary Clinton to the "Late Show" when she was making her Senate run
Barack Obama became the first-ever sitting U.S. president to appear on the "Late Show" in 2009.
After a week of shooting in L.A., Letterman was reunited with his mentor Johnny Carson, who got behind the desk one last time. It would end up being Carson's last TV appearance.
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From Bill Murray to President Obama, we look back at some unforgettable visitors on the host’s “Late Night” and “Late Show”
Bill Murray was Letterman's first guest on "Late Night," and the actor always makes a splash when he returns, including fabulous entrances as Liberace and Peter Pan.