Former MSNBC anchor Rita Cosby is in for a bit of trouble if Larry Birkhead and Howard K. Stern, about whom she says are in a “relationship” in her forthcoming tell-all book, go after her and sue.

Rita Cosby has penned a provocative little book, titillatingly titled “Blond Ambition: The Untold Story Behind Anna Nicole Smith's Death,” due for release any day now. In it, she explains several personal theories.

The one that has Larry Birkhead and Howard K. Stern all wound up says that the two are in a “relationship” and that it was their plan all along for Birkhead to get custody of Dannielynn, his biological daughter with Anna Nicole Smith, while Stern would be named executor of her estate.

TMZ.com reports that Cosby could have documents that prove the deal between the two men. The celebrity gossip web site also says Cosby is basing her hypothesis of a relationship between them on the testimony from Jackie Hatten, described as a friend of Anna Nicole’s.

Jackie Hatten is the sister of Mark Hatten, a former boyfriend of Anna Nicole’s, now serving time in prison after stalking the Playboy Playmate.

Birkhead and Stern are not about to accept any of Rita’s allegations and have threatened to sue her.

TMZ reports that the “Today” show decided to cancel a special interview that it had planned with Cosby about her book, after being threatened with a lawsuit.

This is starting to sound a lot like the time when O.J. Simpson first announced, last October, that he had written a book titled “If I Did It” in which he described how he would have murdered his ex-wife and her friend – had he murdered them. His book and accompanying interview on Fox were both scrapped at the time.

Howard K. Stern’s lawyer, Lin Wood, has apparently already reacted to Cosby’s upcoming book (and the dirty secrets allegedly unearthed in it), calling it “false and defamatory.”

The New York Daily News quotes Wood saying, “It appears that Ms. Cosby has joined the ranks of tabloid journalists who are willing to publish the print equivalent of sewerage to engage in character assassination for profit.”

Birkhead himself told TMZ, “If that's what's in her book, then she'll be sued. And on top of that, there will be other individuals sued over confidential information in my custody case.”

After Anna Nicole’s sad death on February 8, 2007, both Birkhead and Stern claimed to be the father of the former model’s 5-month-old baby, Dannielynn. Birkhead had been her boyfriend, while Stern was in a relationship with Anna at the time of her death.

Court-ordered DNA tests showed that Birkhead was the father. He received custody of Dannielynn (and soon posed on the cover on OK! magazine with his newfound daughter.) Dannielynn turns 1 this Friday, but the aforementioned magazine will not pay Birkhead $1.7 million anymore for exclusive coverage of the birthday party.