Evil Dave Letterman - The Howard Stern Show

Van Dam's first appearance on the The Howard Stern Show was on December 8, 1999, where using his "Letterman voice", called in making jokes about Jay Leno, Letterman's rival late night talk show host. The next day, Stern read an article from the New York Post explaining that an advisor of the real Letterman had to announce that the caller was actually not the real Letterman. Van Dam was then called back to congratulate, and showed his interest in the impression and the reaction it got. Stern then told Van Dam that he would contact him to make more appearances as well as writing "filthy" lines that the real Letterman would not say.

Van Dam would continue calling in the show throughout 2000 until he made his first live studio appearance on July 27, 2001 where he took part in The Gossip Game with Mike Walker, a weekly show segment, under the identity of "David E. Letterman". The visit was a success, and Van Dam would make three to five studio visits a year from 2001-2005 until Stern left terrestrial radio.

Following the show's move to Sirius XM Radio in January, 2006, Van Dam's first appearance on Howard 100 was during an episode of Tissue Time with Heidi Cortez, before the show's inaugural broadcast. Van Dam's first call was on January 13, 2006, that was planned as a series of pranks to new show announcer George Takei. Van Dam called in as Letterman to dupe Takei in reading a Top 10 list about William Shatner on the day's Late Show with David Letterman.