(LONDON) — Prince Harry will break royal precedent once again when he testifies this week in court, becoming the first British royal to do so in more than a century.

Harry, the duke of Sussex, is expected to take the stand Tuesday and Wednesday in his lawsuit against Mirror Group Newspapers, the publisher of the Daily Mirror.

Harry’s attorney, David Sherborne, said in court Monday that Harry would need to testify on Tuesday because of a late flight to the U.K. after celebrating the birthday of his daughter, Lilibet, who turned 2 on Sunday.

Harry and his wife Meghan, the duchess of Sussex, live in California with Lilibet and their 4-year-old son, Archie.

Harry and 100 other celebrities, including the estate of the late George Michael, are suing Mirror Group Newspapers for alleged misuse of private information between 1991 and 2011, including phone hacking and intercepting voicemails.

Harry’s legal team has accused the newspaper publisher of unlawfully gathering information on an “industrial scale.”

Mirror Group Newspapers has denied the claims, saying its reporters found the information through lawful reporting.

If Harry takes the stand Tuesday as expected, he will be the first member of Britain’s royal family to testify in a court case since the late 19th century.

“Harry is somebody that is very clear in what he wants to achieve. He believes he has been treated badly by this newspaper group,” said ABC News royal contributor Robert Jobson. “He believes he’s had his phone hacked by this newspaper group and therefore is determined, as he is right, to be compensated for it, and to receive an apology.”

Since stepping down from his role as a senior working royal in 2020, Harry has made no secret of his disdain for the British tabloid media.

The lawsuit against the Mirror Group Newspapers is one of six lawsuits that Harry, the youngest son of King Charles III, is currently waging against the British tabloids.

He made an unexpected appearance in a U.K. courtroom in March for a hearing on a lawsuit that he, Elton John and other celebrities have brought against Associated Newspapers Ltd., the publisher of the Daily Mail, The Mail on Sunday and the MailOnline.

The case, first announced last year, alleges the celebrity defendants are “the victims of abhorrent criminal activity and gross breaches of privacy,” according to a press release shared last year by Hamlins, the London-based law firm representing Harry in the case.

Harry told ABC News’ Michael Strahan in January that the lawsuits he is involved in are his attempt to bring about real change when it comes to the media coverage of celebrities and the royal family.

“I’m in this to be able to say, ‘Draw a line. Enough. We can all move on and get on with our lives,"” he said. “But if this continues, then I’m naturally, deeply concerned that what has happened to us will happen to someone else.”

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