The Welsh actor Catherine Zeta-Jones was appearing in a Los Angeles court yesterday to give evidence against a 32-year-old unemployed woman accused of sending letters threatening to kill her.

Ms Zeta-Jones was expected to explain how her life, and that of her husband Michael Douglas, had been ruined by a series of letters sent by 32-year-old Dawnette Knight to Mr Douglas's father, the 87-year-old film actor Kirk Douglas.

The 14 letters included a fake obituary notice, titled "Funeral invitation".

"Home grown celebration for Catherine Zeta-Jones," read the card. "Obituary Mrs Catherine Zeta-Jones. Goodbye to the solemnized ASAP Time place, Catholic church, Wales."

Another letter alleged that Ms Zeta-Jones was pregnant by fellow actor George Clooney. Other letters purported to be from British television presenter John Leslie and his girlfriend Abi Titmuss, while Ms Knight is also accused of threatening to kill Ms Zeta-Jones in telephone calls to a Bermuda hotel partly owned by Mr Douglas.

Ms Knight, who was arrested last month at her Beverley Hills home, is on bail of $600,000 (£329,092).

She is charged with making threats against Ms Zeta-Jones "with the intent that she be placed in reasonable fear for her safety and the safety of her immediate family".

The offences are alleged to have been committed between January 2003 and May 2004. If convicted, she faces a maximum sentence of 19 years in prison.

Ms Knight has admitted writing letters to the Douglas family, claiming in a letter last month that she was a "confused young woman", obsessed with Michael Douglas.

Her lawyer said on Monday that she had a "girlish crush on Michael Douglas" and sent him a note telling him she would show him "a good time". But he said he doubted that she had written all the letters.

"We haven't gotten the sum of the language in the letters, which no heterosexual woman would ever have written," he said.

"So I'm not convinced that my client was the one behind the awful things that are in those letters."

Ms Knight's fiancé, Ronald Calvin, described her as a "God-fearing woman", and said she had "every intention of pursuing her career as a child psychologist and loving wife to myself and, hopefully, the mother of my children".

The letter signed "John Leslie" said: "You need to let Catherine know if she hurts Michael I will hire someone to kill her. She will be taken care of ASAP."

The letter purporting to be from Abi Titmuss was the only one of the 14 not to be handwritten.

Instead, it consisted of letters cut out from newspapers. It said: "We will kill Catherine Zeta-Jones soon."

The telephone call to the Bermuda hotel, in which Ms Knight is alleged to have muffled her voice, said: "You let Michael know we are going to kill his wife - kill that bitch."

Another letter, purporting to be from Eric Douglas, the half-brother to Michael Douglas who died this month, read: "You know we really want to get her when she is by herself or maybe when she is on location.

"She will be dead before the blink of an eyelid."