How Prince William and King Charles Feel About Prince Harry Testifying in Court: Royal Expert (Exclusive)

Royal expert Katie Nicholl shares how this trial could affect the royal family as a whole.

This week, Prince Harry has been testifying at the High Court in London, England, in a tabloid case against Mirror Group Newspapers  (MGN). In his witness statement released Tuesday, the Duke of Sussex outlined how the British media company's stories about his personal life have impacted his relationships, mental health and safety.

On Wednesday, Harry continued to testify in court, and royal expert Katie Nicholl tells ET that the royal family has been apprehensive about him speaking out. 

"My sources tell me that [King Charles III] and [Prince William] were very wary about Harry going into the witness box," Nicholl explains. "I think when you see what came out of Harry's evidence and his witness statement, you can understand why."

In his written testimony, Harry addressed speculation that his biological father is Princess Diana's former partner, Major James Hewitt, and not King Charles, and referenced an article published by The People in December 2002 titled "Plot to rob the DNA of Harry."

"Numerous newspapers had reported a rumor that my biological father was James Hewitt, a man my mother had a relationship with after I was born," Harry stated. "At the time of this article and others similar to it, I wasn't actually aware that my mother hadn't met Major Hewitt until after I was born."

Harry also claimed that his phone was hacked, and shared several instances where voicemails were allegedly erased or never seen.

"I remember on multiple occasions hearing a voicemail for the first time that wasn’t new – I would simply put it down to perhaps a technical glitch... or even just having too many drinks the night before and having forgotten that I’d listened to it," he said. "I also distinctly remember people saying to me 'Did you not get my voicemail?'. I was like, 'No', and sometimes I would go back into my voicemail to look for it, but still couldn’t find it."

As this case continues, Nicholl notes that there are other "details that the royal family really don't want to come out." 

According to Reuters, Harry is the first senior member of British royal family to give evidence in court in 130 years --but he won't be the only one speaking out in this case. Over 100 people are suing MGN for alleged illegal activity between 1991 and 2022, with Harry being one of four representative claimants whose cases were selected for trial. The trial began on May 10 and is expected to last seven weeks.

MGN is the publisher of the Daily MirrorSunday Mirror and The Daily Express, among other newspapers.