NEW YORK - The king of America's special brand of late-night television, David Letterman, broadcasts his final show Wednesday, closing the door on a pioneering, 33-year-long career that inspired a generation of comedians.
Not only is he the longest-serving nighttime US talk show host, but his unique style of caustic and at times grumpy humour set him apart even if rivals pulled in more viewers.
He announced his retirement in 2014 and as the clock as ticked down, there has been an avalanche of tributes to his extraordinary career from emotional celebrities and stacks of columns written in the press.
Wednesday's episode of the "Late Show with David Letterman" will be the broadcaster's 6,028th television show of his career when it airs at 11:35 pm (0335 GMT) from the Ed Sullivan Theater in New York.
Other than featuring rock giants Foo Fighters, whom the 68-year-old has described as his favourite band, CBS television has kept the lid on the rest of the show, promising only many surprises.
Hollywood comedy giants Steve Martin and Jim Carrey were among those reportedly spotted heading into the theatre earlier Wednesday.
Bill Murray and Bob Dylan were guests Tuesday, Tom Hanks on Monday, while Oprah Winfrey, George Clooney, Julia Roberts, Al Pacino and Bill Clinton featured last week.
Critics have praised Letterman for combining innovative and odd-ball antics with traditional interviews, and for inspiring some of most the talented comics working today in Britain and the United States.
"I'm naked and afraid," Letterman told CBS Sunday. "Any enormous uprooting change in my life has petrified me," he said.
But once through the other side "the reward has been unimaginable," he added.
Letterman got his first comedy show on NBC in 1982, before defecting to CBS in 1993 to host the "Late Show" after the biggest career disappointment of his career -- losing out to Jay Leno as host of the "Tonight" show.
But initially, his ratings eclipsed Leno's on NBC. Then Leno landed an interview with British actor Hugh Grant in 1995, just after he was caught with a prostitute, and Letterman's ratings never caught up.
Sarcastic, at times angry and scathing, some celebrities admitted they feared him, and ended up in his crosshairs.
Singer Cher once quipped on air that she thought he was an "a**hole" and yet he enjoyed an on-camera chemistry with many of guests.
Through it all, Letterman won 12 Emmy awards - the most highly prized accolade in American television - and was nominated for a total of 67, including every year from 1984 to 2009.
Other stand-out moments also set him apart.
After the horror of the September 11, 2001 attacks on the United States, Letterman was the first comedian to go back on air - six days after the Al-Qaeda hijackings that killed some 3,000 people.
In January 2000, he underwent a quintuple heart bypass. Five weeks later, he was back on air with his doctors as his guests.
In 2009, he admitted to affairs with female staffers and apologised on air, alongside his wife and his team. He kept his job.
Today a younger, social-media savvy generation of late-night comedy hosts dominate the airwaves; Jimmy Fallon, 40, on NBC; Jimmy Kimmel, 47, on ABC; and Seth Meyers, 41, on NBC at 12:35 am.
Letterman will be replaced from September 8 by Stephen Colbert, 51, who until last December hosted the "Colbert Report" on Comedy Central.
"They didn't push me out," Letterman told The New York Times. "When Jay was on... I thought, this is still viable - an older guy in a suit. And then he left, and I suddenly was surrounded by the Jimmys."
Married to long-time companion Regina and the father of 11-year-old Harry, he compared retirement to a "punch to the head."
"For the first time since Harry's been alive, our summer schedule will not be dictated by me. It will be entirely dictated by what my son wants to do," he told the Times.