David Letterman to Retire, Step Down From 'Late Show' in 2015

And another late-night icon gets ready to say goodbye.

Less than two months after his longtime rival Jay Leno stepped down from NBC's "Tonight Show," David Letterman has announced he'll retire and step down from CBS's "Late Show" in 2015.

Letterman addressed the "Late Show" audience at Thursday's taping, saying, "The man who owns this network, Leslie Moonves, he and I have had a relationship for years and years and years, and we have had this conversation in the past, and we agreed that we would work together on this circumstance and the timing of this circumstance. And I phoned him just before the program, and I said ‘Leslie, it’s been great, you’ve been great, and the network has been great, but I’m retiring.'"

[Photos: 20 Classic 'Late Show' Moments We're Glad We Stayed Up Late For]

“I just want to reiterate my thanks for the support from the network," Letterman added, "all of the people who have worked here, all of the people in the theater, all the people on the staff, everybody at home, thank you very much. What this means now is that Paul and I can be married.”

“We don’t have the timetable for this precisely down — I think it will be at least a year or so, but sometime in the not-too-distant future, 2015 for the love of God, in fact, Paul and I will be wrapping things up and taking a hike,” he concluded, receiving a standing ovation from the Ed Sullivan Theater audience.

The news of Letterman's retirement first broke, curiously enough, from a tweet by former REM bassist Mike Mills, who's performing on tonight's "Late Show":

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CNN reporter Brian Stelter later confirmed the news:

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President Barack Obama even tweeted his reaction to Dave's departure:

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CBS president and CEO Les Moonves released a statement as well: "When Dave decided on a one-year extension for his most recent contract, we knew this day was getting closer, but that doesn’t make the moment any less poignant for us. For 21 years, David Letterman has graced our Network’s air in late night with wit, gravitas and brilliance unique in the history of our medium. During that time, Dave has given television audiences thousands of hours of comedic entertainment, the sharpest interviews in late night, and brilliant moments of candor and perspective around national events."

"He’s also managed to keep many celebrities, politicians and executives on their toes – including me. There is only one David Letterman. His greatness will always be remembered here, and he will certainly sit among the pantheon of this business. On a personal note, it’s been a privilege to get to know Dave and to enjoy a terrific relationship. It’s going to be tough to say goodbye. Fortunately, we won’t have to do that for another year or so. Until then, we look forward to celebrating Dave’s remarkable show and incredible talents.”

Watch Letterman swig vodka with Martha Stewart on a recent "Late Show":

Letterman has hosted CBS's "Late Show" since 1993, after a well-publicized battle that saw him lose out on hosting "The Tonight Show" when NBC opted for Leno. Before that, he hosted NBC's "Late Night," following Johnny Carson's "Tonight Show" from 1982 to 1993.

Now the big question: Who will replace Dave? ABC's Jimmy Kimmel just told TV Guide last month that if Letterman ever retired and asked him to step in, "I'd definitely consider it." Chelsea Handler is on the way out at E!, and will be free to jump ship to a new network by year's end. And don't forget Conan O'Brien, whose contract with TBS ends in November 2015 and has always had a strong rapport with Letterman.

More to come as this story develops...

"Late Show With David Letterman" airs weeknights at 11:35 on CBS.