Who in the World is Stephanie Birkitt?!

If you watch ‘The Late Show’ regularly, you just might recognize Stephanie Birkitt. She appeared countless times on the program, in skits as herself and as a gift certificate-bearing assistant named “Vicki.” Birkitt is also reportedly the woman at the center of alleged extortion plot against her ex-boss, David Letterman, who Thursday admitted to having sexual relationships with several of his female staffers.

According to TMZ, Birkitt is the girlfriend and former roommate of Robert “Joe” Halderman, the ’48 Hours’ producer who was indicted Friday in a plot to blackmail Letterman out of $2 million in exchange for his silence on the affairs.

Halderman was reportedly in possession of Birkitt’s diary and certain photos that he said would damage Letterman if made public.

Birkitt worked for Letterman for over a decade, and rose in the ranks to be his assistant. On several occasions, she appeared on the air in various skits and gags, including reports from the Winter Olympics in both 2002 and 2006.

It is believed Birkitt and Letterman had a sexual relationship that ended before his marriage and the birth of his son, Harry, in 2003. Sources tell RadarOnline.com that Birkitt is reportedly “mortified Halderman is using her fling with Letterman to blackmail her boss.”

Birkitt is a 1997 graduate of Wake Forest University and Gawker is reporting that she received “extra compensation for duties as his First Assistant, in the form of Letterman picking up the tab for her graduate law studies at the Yeshiva University Law School.”

Thanks to Popeater.com for the info and The Examiner for the photo.