Anna Nicole Smith

Anna Nicole Smith’s lawyer and companion Howard Stern has filed a £30 million libel action against author Rita Cosby and her publisher over a book that claims Stern and Smith’s ex-boyfriend, Larry Birkhead, had a sexual encounter.

The writ, filed in federal court in New York, seeks £5 million in compensatory damages and £25 million in punitive damages from Cosby — who wrote Blonde Ambition: The Untold Story Behind Anna Nicole Smith’s Death — and Hachette Book Group USA.

The book, which hit stores in September, claims that besides the alleged sexual encounter, Birkhead and Stern worked together after former Playboy Playmate Smith’s death to manipulate the media and maximise profits.

The lawsuit says that the book falsely accuses Stern of, among other things, criminal lewd acts, homosexual acts, illegal possession and use of cocaine, conspiring to commit murder and kidnapping for ransom.

“Defendants have exploited Ms Smith’s life and death by publishing false and defamatory factual accusations against” Stern, according to the 65-page lawsuit filed by Atlanta, Georgia, lawyer Lin Wood.

Wood said in a statement that Cosby and her publisher “made a conscious decision to smear the personal and professional reputation” of Stern for financial gain.

A spokesman for Cosby referred calls to Evan Boorstyn, a spokesman for the book’s publisher.

He did not immediately return a call seeking comment.

Both Birkhead, the father of Smith’s infant daughter, and Stern, Smith’s long-time lawyer and companion, had threatened to sue soon after the book was published.

Yesterday’s lawsuit lists only Stern as a plaintiff.

A lawyer for Birkhead, ML Trope, said “it’s just a matter of time” before his client filed a libel suit of his own.

Stern’s lawsuit says Stern’s lawyer advised Cosby and her publisher before the book was published not to include any defamatory statements about Stern.

The suit says that Cosby and her publisher never contacted Stern to verify the truth of allegations against Stern in the book.

Birkhead acknowledged meeting with Cosby several times after Smith’s death in February.

But he flatly denied that he and Stern shared a sexual tryst.

Cosby, a former MSNBC news website correspondent, claimed there was a videotape of the alleged encounter and that one of Smith’s former employees had seen the former Playboy Playmate watching it.

But Birkhead has said no tape could exist because the encounter did not occur.

Birkhead also has denied the book’s claim that he and Stern made a “secret deal” about finances and the custody of Smith’s daughter, Dannielynn.

Cosby has said she expected backlash from Birkhead and Stern when she started writing the book in April.