A lawyer for two women who worked for Anna Nicole Smith said Monday a new book falsely uses them as a source for a claim the former Playboy Playmate's lawyer had a videotaped sexual encounter with her boyfriend.

Quethlie Alexis and Nadine Alexie, who worked as nannies for Smith in the Bahamas, never spoke to the author of the book, former MSNBC host Rita Cosby, and never told anyone about any sexual encounter between Smith's lawyer Howard K. Stern and boyfriend Larry Birkhead, attorney Elizabeth Thompson said.

"They don't know one way or another if it happened," Thompson told The Associated Press.

Cosby's book, "Blonde Ambition: The Untold Story Behind Anna Nicole Smith's Death," says the nannies, accompanied by a lawyer, told a private investigator that Smith liked to sit in bed and watch a videotape of Birkhead and Stern having a sexual encounter.

Cosby, who is in the Bahamas this week, said she never spoke to the nannies but stands by her book, which also attributes the claim of a sexual encounter to a friend of Smith's.

"We have a number of sources," she said. "We have it attributed directly to a private investigator who specifically said that."

Stern, who was Smith's companion before she died, has called the claim "ridiculous," and last week filed a $60 million libel lawsuit against Cosby and her publisher, Hachette Book Group USA Inc. An attorney for Birkhead has said he also plans a lawsuit.

Smith died of an accidental drug overdose in Florida in February at age 39. Stern — who had been living in the Bahamas with the former model — initially claimed to have fathered Smith's young daughter, Dannielynn, but Birkhead eventually proved he was the father. The baby could inherit millions from the estate of Smith's late husband, Texas oil tycoon J. Howard Marshall II.

The nannies are Haitian immigrants who worked at the gated, waterfront home shared by Smith and Stern on New Providence Island.

Thompson is their third attorney since the nannies became highly sought after by journalists following the September 2006 death of Smith's 20-year-old son Daniel in the Bahamas, the former model's own death and the legal battle over her burial and the custody fight for Dannielynn.

The nannies said they have spoken with a private investigator who they believed was working for an attorney for Smith's mother. But they never mentioned any alleged encounter between Birkhead and Stern, the lawyer said in a meeting with several reporters in Nassau.

Cosby said she was hoping to speak with the nannies while in the Bahamas.

"It was obvious that they were not readily accessible and we thought it was important to come down here and speak," she said.