13 of David Letterman's Most Memorable Celebrity Moments

David Letterman has been delighting audiences since the first episode of Late Night With David Letterman aired on Feb. 1, 1982. In 1993, the comedian and his crew moved to CBS, and the Late Show With David Letterman was born. The now 68-year-old has built quite the legacy, and ETonline has 13 of the biggest moments that will make you sad that he is retiring on May 20, 2015.

In 1995, actress Drew Barrymore gave him a birthday he would never forget as she flashed him during a taping on April 12.

On the first taping of the Late Show on Aug. 30, 1993, the comedian spray painted Letterman's desk.

The late actor appeared on the second taping of the Late Show on Aug. 31, 1993 as the duo shared a night of laughter.

The "If I Could Turn Back Time" singer fed cake to Dave for his birthday on April 12, 1999.

The U.S. vice president and Letterman cracked an ashtray with a hammer together on Sept. 8, 1993.

For Letterman's 5th anniversary of the Late Show, Martin joined the host to help him celebrate on Nov. 23, 1998.

The retired NBA player gave Letterman a new look on Aug. 20, 1996.

The "Material Girl" has a history with the Late Show. In 1994, she promoted her new album, Music, but did not return for a sit-down interview until Nov. 3, 2000. She took another three-year break before coming back, and this photo shows her return as a guest on Nov. 11, 2003. Before she entered, Letterman told her he didn’t want any "awkward moments!"

The Bridget Jones' Diary actress had some serious fun with Letterman as she broke open a guacamole-laden piñata with him on Aug. 20, 2009.

The Hunger Games star got cozy with Letterman under a blanket when she visited on Nov. 20, 2013.

The fitness personality made a flying entrance -- literally -- and got sprayed by Letterman with a fire extinguisher on May 12, 2000.

Lohan gave her first interview since Nov. 2012 to Letterman. On April 8, 2013, she talked about her upcoming trip to rehab and guest roles in the series "Anger Management" and the movie, Scary Movie 5.

Oprah paid Letterman a visit on Dec. 1, 2005, 16 years after her previous visit. Following the interview, the host proved to be a true gentlemen by escorting her across 53rd Street to the opening of her Broadway Show, The Color Purple.