David Letterman's former assistant Stephanie Birkitt allegedly involved in extortion plot

David Letterman’s former assistant Stephanie Birkitt has been identified as one of the women involved in the David Letterman extortion plot, Huffington Post says.

Birkitt lived with alleged blackmailer Robert "Joe" Halderman, who claimed he "was in possession of Birkitt's diary, correspondence and photos -- which he says incriminated Letterman."

Sources tell RadarOnline.com that Birkitt is reportedly "mortified Halderman is using her fling with Letterman to blackmail her boss."

Birkitt, a 1997 graduate of Wake Forest University, interned in the writers' department at the "Late Show" in 1996.

She also worked at "48 Hours" -- where Halderman worked as a producer before Birkitt applied to be Letterman's assistant.

And the rest is TV sex scandal history.

Sleeping with your assistant, Dave? Tres Clintonesque. Let's hope there wasn't a cigar involved.