From TMZ-

David Letterman, the longest-serving late-night talk show host in TV history, has just announced his retirement.

Letterman made the announcement during the taping of his show Thursday in New York, telling the audience his last show will take place in 2015.

Letterman began his Hollywood career as a stand-up comedian in the late 1970s, appearing several times on "The Tonight Show Starring Johnny Carson." He got his morning show in 1980 and began his late night career in 1982 on NBC with "Late Night with David Letterman."

10 years later in 1992, Letterman moved to CBS to host "The Late Show with David Letterman," after Jay Leno was tapped to replace Johnny Carson on NBC.

Letterman's CBS contract is scheduled to expire next year and Letterman won't be re-upping.