Andrew Mountbatten-Windsor is expected to give evidence via videolink in the trial of a man accused of threatening him.
Alex Jenkinson is charged with using threatening, abusive or insulting words or behaviour towards the former prince during an incident in Norfolk on 6 May.
It is alleged that the 39-year-old, from Stowmarket, Suffolk, caused Andrew to "fear unlawful violence".
A court heard on Wednesday that Jenkinson will stand trial on 21 December.
The case had originally been due to open on Wednesday, but was delayed by chief magistrate Paul Goldspring because of concerns about the defendant's mental health.
The court heard that he underwent a psychiatric assessment on Tuesday, and a report is due to be prepared for early August.
Part of the case relates to an incident when Andrew was out walking his dogs in Wolferton, near his Marsh Farm property.
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At Wednesday's hearing, Westminster Magistrates' Court heard that online searches on Jenkinson's phone were expected to form part of the evidence at trial.
Jenkinson, who was not at Wednesday's hearing, has pleaded guilty to failing to provide a specimen of blood while in custody on 6 May.
But he has denied the public order offence against Andrew Mountbatten-Windsor and has also pleaded not guilty to a further charge of using threatening, abusive or insulting words or behaviour with intent to cause fear or provoke unlawful violence against a man, Stephen Terry, in King's Lynn, on 5 May.
Jenkinson is on bail under the conditions he must not to go near a number of sites linked to the royal family, including Sandringham, Buckingham Palace, Balmoral, Windsor and Highgrove.
He must also not try to contact Andrew directly or indirectly, or enter Norfolk, the court heard.
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