Meet “Late Show” assistant Stephanie Birkitt — the woman unknowingly at the center of the extortion case against David Letterman and the former girlfriend of “48 Hours” Robert “Joe” Halderman, the man accused of doing the actual blackmailing. Confused? Good. Radar Online says

Stephanie Birkitt met Halderman at CBS about 15 years ago. At the time, Halderman was in one of his two past marriages, and Halderman did not have a relationship with Birkitt.

Birkitt later got a job on Letterman’s show and has worked there for more than a decade, often appearing on air.

Our source [say] that Birkitt and Letterman slept together for a period of time before he married his girlfriend Regina had their son Harry. After Halderman divorced, the source says he got involved with Stephanie and she lived with him in Connecticut.

The source says Birkitt told Halderman that she had had sex with Letterman.

So it seems that while they were living together (and without her consent), Halderman went through Birkitt’s personal effects for proof of hers and Letterman’s affair to use to blackmail the talk show host, including

Copies of parts of a diary and correspondence belonging to Birkitt, [along with] documents, letters, emails and photos.

Jesus, I didn’t know anyone other than 8th grade girls kept actual diaries. What a stupid idea. I guess you never know when all your puffy hearts and triple-underlined “Mrs. Stephanie Lettermans” will come back to bite you in the ass.

David Letterman admitted on CBS’ “Late Show” last night that he had been the victim of a $2 million dollar extortion attempt by a producer at “48 Hours” stemming from his sexual encounters with several women currently in his employ. Letterman, of course, has been married to Regina Lasko since March, after dating her for 23 years, but in his defense, she looks like she should be in construction, or the very least a member of the East German Hammer Throwing Team. According to Variety:

On the show, Letterman sat down behind his desk and [said he had] received a package three weeks ago from someone who claimed to have information about alleged sexual relations he has had with female employees of the “Late Show.”

“I get to looking through it and there’s a letter in the package and it says, ‘I know that you do some terrible, terrible things. And I can prove that you do these terrible things.’ Sure enough, contained in the package was stuff to prove that I do terrible things,” Letterman said.

The host said the alleged extortion suspect claimed he planned to write both a movie screenplay and a book based on what he knew — that Letterman had engaged in sex with staffers.

Letterman said the individual threatened to go public with the allegations unless Letterman paid the person $2 million.

The host, under advisement of his attorney, met with the man on three different occasions. According to Letterman, the suspect even made it clear he knew what he was doing was illegal.

Letterman told his audience that he then contacted the Manhattan District Attorney’s Special Prosecution Bureau. The meeting with the D.A. led to a sting operation, in which Letterman met with the individual and handed the person a fake $2 million check. That person was arrested on Thursday.

$2 million? Are you kidding me? In this economy? If the extortionist had kept it reasonable, say, $500,000 and maybe the property rights to Paul Shaffer, he would have his money and his little muppet, too. Now all he’ll have to keep him company are Angelo the Serial Stabber and the nickname “Cream of Meat.”

David Letterman announced during the Monday taping of his CBS Late Show that he had married longtime girlfriend and mother of his child, Regina Lasko. Us Weekly says:

“On Thursday, at 3 p.m., March 19, 2009, at the Teton County Courthouse in Choteau, Montana, I was married to Regina Lasko,” Letterman said about 20 minutes into the show, before he read the “Top 10″ list.

Letterman and Lasko — who began dating in 1986 when Lasko worked for him on his show — welcomed Harry in November 2003.

If you’re wondering why it took him 23 years to propose, I’m guessing it’s because it took fifteen just to convince him she wasn’t really a lesbian, and then maybe another seven before he finally gave up looking for her secret ax and blue ox. Congratulations to the happy couple!