(LONDON) — Prince Harry took to the witness stand Tuesday in a U.K. courtroom, becoming the first British royal to do so in more than a century.

Harry, the duke of Sussex, was grilled by the defense team in his lawsuit against Mirror Group Newspapers, the publisher of The Daily Mirror.

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.

On the witness stand, Harry said the articles published about himself and his family played a destructive role in his childhood and provoked feelings of paranoia in him.

“As a teenager and in my early 20s, I ended up feeling as though I was playing up to a lot of the headlines and stereotypes that [the tabloid press] wanted to pin on me mainly because I thought that, if they are printing this rubbish about me and people were believing it, I may as well ‘do the crime,’ so to speak,” Harry said in his prepared witness statement. “It was a downward spiral, whereby the tabloids would constantly try and coax me, a ‘damaged’ young man, into doing something stupid that would make a good story and sell lots of newspapers.”

He continued, “Looking back on it now, such behavior on their part is utterly vile.”

Harry’s legal team has accused Mirror Group Newspapers of unlawfully gathering information on an “industrial scale.”

Mirror Group Newspapers is contesting the claims, saying in the 33 articles being examined by the court that its reporters found the information through lawful reporting.

Harry’s testimony in the case is expected to continue on Wednesday.

The prince traveled to the U.K. just prior to his testimony Tuesday because of a late flight to the U.K. after celebrating the birthday of his daughter, Lilibet, who turned 2 on Sunday, according to his attorney.

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

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. In his witness statement, Harry said it he has “a very difficult relationship with the tabloid press in the U.K.”

“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.”

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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