Zeta Jones said she had an anxiety attack following violent phone calls

The Oscar-winner spoke at a Los Angeles Superior Court preliminary hearing in a case against Dawnette Knight, 32.

"I've never in my life had anything or had anyone say anything to me so satanic," said Zeta Jones, 34.

"I can't even imagine how a sane human being could have these images locked in their brain."

'Constant fear'

Defence lawyer Richard Herman said outside court that Ms Knight had been upset by a false tabloid report alleging an affair between the actress and actor George Clooney, a co-star in the upcoming film Ocean's 12.

"That upset my client and she wrote her telling her to stop," Mr Herman said.

The Welsh actress said she had a severe anxiety attack after two violent phone calls were made in May to her hotel in Amsterdam, where the film was being shot.

She was in constant fear while filming scenes in the city and wondered if the letter-writer was among crowds of fans, Zeta Jones said.

Dawnette Knight has said she is sorry for any "distress"

She read extracts from 19 of the threatening letters to the court.

Some referred to the violent deaths of President Kennedy, Nicole Brown Simpson and Sharon Tate - the actress who was a victim of the 1969 Manson Family killings - and contained graphic details of how Zeta Jones would be killed.

"We are going to slice her up like meat on a bone and feed her to the dogs," said one letter quoted by Zeta Jones.

Ms Knight has pleaded not guilty to 25 counts of making criminal threats and stalking.

Judges must decide if there is enough evidence for her to stand trial.

'Nervous breakdown'

Outside court defence lawyer Mr Herman said the actress did not read the bulk of the letters until after Ms Knight was arrested at her Beverly Hills home on 3 June.

He said having Zeta Jones read them in preparation for the hearing was a "setup for the prosecution".

Earlier on Wednesday her husband Michael Douglas said Zeta Jones was driven close to a nervous breakdown by the threats.

"She was hysterical... she was fainting. She could not get any air. She showed all the signs of having a nervous breakdown," Douglas said.

Michael Douglas said he hid an initial threatening call from Zeta Jones

He told the court the first threat to his wife he was aware of was in a telephone call made in March to a hotel his family owns in Bermuda.

He said he did not mention the call to his wife at first, fearing it would "upset her tremendously".

But once he discussed the matter with authorities, he found that his father - film legend Kirk Douglas - had already received "very graphic" threatening letters.

Douglas said the knowledge displayed by the letter-writer - coupled with such details as a description of the hallway of a home in which the couple had once lived - was particularly chilling.

"The proximity made us terrified," he said. "There was a knowledge in these letters that was deeply unsettling."

'No explanation'

Ms Knight's lawyer, Richard Herman, revealed last month that Ms Knight had written to Zeta Jones and Kirk Douglas apologising for any "distress" she may have caused.

The letter said Ms Knight was infatuated with Zeta Jones' husband.

"I was a confused young woman infatuated with Michael Douglas and have no rational explanations for my actions," she wrote.

Her letter to the actress said she would "have never done anyone any harm and would never harm anyone" but admitted her obsession with Michael Douglas.