(Sept. 3) - A forthcoming book about the death of Anna Nicole Smith alleges that two of the men who claimed to be the father of her daughter, Dannielynn, were lovers.

'Blonde Ambition: The Untold Story Behind Anna Nicole Smith's Death,' was written by former MSNBC reporter Rita Cosby. In the book, Cosby claims Smith and a friend –- identifed as Jackie Hatten -- once happened upon Howard K. Stern and Larry Birkhead half-undressed and intertwined, reports the New York Daily News.

"Their bodies were intermingled," said Hatten, according to a copy of the book obtained by the Daily News. "It was obvious what was happening."

The book says Smith had a video of the men engaged in oral sex that she would watch regularly.

Birkhead responded to the allegations, telling the Daily News that Hatten "has never met me and she hasn't even seen Anna since 2001." Birkhead goes on to say that Hatten "isn't a credible source" and that her brother "went to jail for stalking Anna. This book is coming from the losers club because they all have axes to grind."

Cosby's book also accuses Stern and Birkhead of keeping Smith drugged. A mixture of prescription drugs killed the actress in February. Police said there was no evidence of foul play.

The two men cut a deal, the book claims, for Birkhead to get custody of Dannielynn in return for Stern being named executor of Smith's estate.

"She got fired and nobody wanted her," Birkhead said in response to Cosby's allegations. "The last story she did was on Anna and now she is doing this book because no one will hire her."

Last week, OK! Magazine issued a press release saying it would not be running photos of Dannielynn's first birthday as planned, citing "shocking" allegations that were "potentially incriminating."

In response, Birkhead threatened to sue. He called the magazine's decision a case of "sour grapes," saying OK! was angry because he wanted to do a photo shoot with US Weekly magazine.

Birkhead also claimed a reporter from OK! e-mailed him warning he’d receive “horrid” coverage if worked with US Weekly on the story.

"They can’t stand it if one other magazine has one other little detail," Birkhead said.