David Letterman saluted by stars on final Late Show
Four US presidents have joined stars including Steve Martin, Tina Fey, Jerry Seinfeld and Foo Fighters to pay tribute to TV host David Letterman on his final late night talk show.
Letterman has bowed out after 33 years and 6,028 late-night broadcasts.
He joked that physicist Stephen Hawking had calculated it "works out to about eight minutes of laughter".
He gave emotional thanks to his family, crew and viewers, saying: "There's nothing I can ever do to repay you."
The 68-year-old began his late-night career on NBC in 1982, before moving to CBS's Late Show in 1993.
His final broadcast began with pre-recorded clips of former US presidents George H and George W Bush and Bill Clinton echoing fellow ex-president Gerald Ford's post-Watergate remark that "our long national nightmare is over".
Barack Obama then appeared to repeat that statement before adding: "Letterman is retiring." The host then joined him to ask: "You're just kidding, right?"
Later in the show, Martin, Fey and Seinfeld were among the stars delivering the final, traditional 'Top 10 list', on the subject of "Top 10 things I've always wanted to say to Dave".
Julia Louis-Dreyfus, with Seinfeld standing nearby, said: "Thanks for letting me take part in another hugely disappointing series finale."
Fey chipped in with: "Thanks for finally proving men can be funny."
And Chris Rock contributed: "I'm just glad your show is being given to another white guy."
Letterman's successor, Stephen Colbert, will take over his slot in September.
During his monologue, the outgoing host joked he had been on the air for so long that the hot show when he started was Keeping Up with the Gabors.
"You want to know what I'm going to do now that I'm retired?" he said. "By God, I hope to become the new face of Scientology."
Letterman became known for his mixture of big-name interviews and comedy features.
They included his irreverent Top 10 lists and segments like Monkey Cam, in which a TV camera was strapped to a monkey while it roamed the studio.
His career has had ups and downs. Testing times included a heart bypass and a sex scandal in which he admitted having affairs with women who had worked on the show.
"When I screw up now, and Lord knows I'll be screwing up, I'll have to go on somebody else's show to apologise," he said on Wednesday.
He ended the show by saying: "The only thing I have left to do for the last time on a television programme: Thank you and goodnight."
Foo Fighters then played their song Everlong over a montage of clips from Letterman's TV career.
FIVE CLASSIC LETTERMAN MOMENTS
- Madonna seeks to shock
Twenty years ago, Madonna had to be censored after swearing more than a dozen times. She also lit up a cigar and gave Letterman her underwear and invited him to smell it. The episode earned some of the highest ratings of Letterman's career.
- Drew Barrymore flashes
With a reputation as a wild child back in 1995, actress Drew Barrymore jumped onto his desk and did a dance before flashing her breasts at the host. "I can't thank you enough for that," Letterman said after regaining his composure.
- Return after 9/11
The host delivered a highly-charged and heartfelt opening monologue after the attacks of 11 September 2001. "If you didn't believe it before, you can absolutely believe it now: New York City is the greatest city in the world," he said.
- Host admits sex scandal
In 2009, Letterman told his audience someone had tried to blackmail him over claims he had had affairs with female members of the programme staff. "I have had sex with women who worked on this show," he admitted. "Would it be embarrassing if it were made public? Perhaps it would. Especially for the women."
- Joaquin Phoenix hoax
Also in 2009, actor Joaquin Phoenix appeared incoherent and unrecognisable, with unkempt hair and bushy beard. "Joaquin, I'm sorry you couldn't be here tonight," Letterman quipped. A year later, Phoenix went back on the show to admit it was a stunt for a mock documentary.