Classical musician Vanessa Mae was frightened and concerned for her safety after an obsessed fan bombarded her with letters, a court heard.
David Martin wrote to Vanessa Mae for eight years, the court heard
David Martin, from Brighton, also kept a diary of the violinist's movements, West London Magistrates' Court was told.
The 56-year-old stated in one of the letters sent over an eight-year period: "I will speak to you, you owe me that."
The court heard he had made attempts to speak to Miss Mae and tried to deliver gifts to her in person.
The violinist said the ordeal caused her "a great deal of distress".
Martin, who pleaded guilty to harassment in October, was due to be sentenced on Friday but the case was adjourned until 24 December for psychiatric assessment.
He was remanded in custody.