Stephanie Birkitt Was David Letterman's Mistress

It's reported Stephanie Birkitt is Letterman's former assistant, and the CBS employee Robert "Joe" Halderman arrested for blackmail is Birkitt's recently-estranged live-in boyfriend.

In David Letterman's earth-shattering confession on The Late Show with David Letterman, he revealed that he was the target of an extortion plot for having sex with staffers.

LimeLife has learned that the mistress being pointed to is 34-year-old Stephanie Birkitt, Letterman's former assistant. She was living with 48 Hours producer Joe Halderman until recently, and it appears Halderman's blackmail strategy may have come as a response to their split. On September 23 Halderman told undercover cops that he was in possession of diaries and other supporting materials that proved the affair between Letterman and Birkitt, and he would expose the materials if Letterman refused to pay him $2 million.

Other than being Letterman's former assistant, Birkitt is a New Hampshire native and 1997 graduate of Wake Forest University with a degree in history. According to Huffington Post, Birkitt interned on The Late Show with David Letterman in 1996 and then took a producing gig at 48 Hours before returning to The Late Show to work as a page and producer, and then as Dave's assistant. In 2004 she said, "I heard there was a job in Dave's office opening up and I applied, because I didn't think I was much of a news hound, as it was a little too serious for my personality." Currently Birkitt is a law student at New York City's Benjamin N. Cardozo School of Law, and incidentally her brother Johnny is a producer for ABC's Dancing With the Stars.

Letterman dated now-wife Regina Lasko for 23 years before marrying her last March. Together they have a son Harry who was born in 2003. Before Lasko, Letterman dated Merill Markoe, a head writer and producer on The Late Show.

Get the early scoop on the David Letterman extortion plot here.