Catherine Zeta Jones' staff contacted police

Dawnette Knight, 32, wrote to Zeta Jones and father-in-law Kirk Douglas apologising for any "distress" she may have caused.

Ms Knight, who pleaded not guilty to making criminal threats and stalking, is being held on $1m (�554,800) bail.

The letter, released by lawyer Richard Herman, said she was infatuated with Zeta Jones' husband Michael Douglas.

"I was a confused young woman infatuated with Michael Douglas and have not rational explanations for my actions," she wrote.

Ms Knight was arrested at her Beverly Hills home on 3 June and charged with one count of stalking and 24 counts of criminal threats.

Dawnette Knight is due in court on 29 June

Zeta Jones staff had called in police, alleging the actress had been receiving threatening letters and phone calls.

Ms Knight is being held in custody and could receive a prison sentence of up to 19 years if convicted.

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

"It would be a wonderful good deed if you would all forgive me so that I can go back to college to finish my studies in child psychology," she pleaded to the actress.