Talk show host David Letterman, left, gestures while talking with Johnny Carson during a taping of the "Tonight Show" at the NBC studio in Burbank, Calif., Aug 30, 1991. (AP Photo/Bob Galbraith)

Tennis player Maria Sharapova, right, greets Late Show with David Letterman host David Letterman after playing tennis with him outside his studio on Monday, April 21, 2008. (AP Photo/Kathy Willens)

David Letterman kisses Madonna goodbye during a skit for "The Late Show with David Letterman" in New York, Wednesday, September 30, 2009. In the scene Madonna and David Letterman eat pizza at Angelo's Restaurant (AP Photo/Charles Sykes)

David Letterman, left, greets New York Mets third baseman David Wright after he threw batting practice outside the "Late Show with David Letterman" studios in New York, Monday, April 14, 2008. (AP Photo/Jeff Zelevansky)

Talk show host David Letterman hosts the late night "David Letterman Show" 1990. (AP Photo)

Robert "Joe" Halderman, 51, appeared in court in Manhattan, Friday, Oct. 2, 2009.

Talk show host Oprah Winfrey, left, is escorted by fellow talk show host David Letterman to the opening night of Winfrey's Broadway play "The Color Purple" in a Thursday, Dec. 1, 2005 photo. (AP Photo/Dima Gavrysh, file)

Talk show host David Letterman departs the Stamford (Conn.) Superior Court house as he walks by Gus Vaillant, building superintendent for the Stamford Court House, left, during a break from jury duty selection, Friday, June 9, 2000. (AP)

NBC talk show host David Letterman clutches the Emmy he was awarded in New York Thursday May 21, 1981 as television's top variety show host. (AP Photo/Ron Frehm)

Robert "Joe" Halderman, 51, appeared in court in Manhattan, Friday, Oct. 2, 2009.

David Letterman at reception in NBC's Studio 6A January 19, 1982 at the announcement of new NBC comedy show "Late Night With David Letterman". (AP Photo/Perez)

David Letterman at the taping of his first talk-comedy hour "Late Night with David Letterman" with guest Bill Murray, February 1, 1982 in New York. (AP Photo/Nancy Kaye)

Comedian David Letterman shown June 5, 1985. (AP Photo/Wally Fong)

NBC "Today" anchor Deborah Norville, who announced on the early morning show that she is expecting a child in the spring, visited with host David Letterman on "Late Night with David Letterman" September 5, 1990. (AP Photo)

Talk-show host David Letterman announces his move from NBC to CBS at a news conference at CBS Studios in New York, Jan. 14, 1993. Letterman's show on CBS will run against NBC's "The Tonight Show" with Jay Leno. (AP Photo/Alex Brandon)

Margaret Ray shouts as she is led into court March 15, 1989, in Norwalk, Conn., after she was charged with breaking into the home of talk show host David Letterman. (AP Photo/Rollin Riggs)

Talk show host David Letterman gestures as he speaks to former President Jimmy Carter during the taping of the "Late show with David Letterman" Tuesday, Sept. 28, 1993.(AP Photo/Alan Singer)

Kelly A. Frank is shown in a photo provided by the Teton County (Mont.) Sheriff taken in Choteau, Mont., March 14, 2005. Frank is the suspect involved in a alleged plot to kidnap David Letterman's baby from the talk show host's Montana home