The Duke of Sussex has begun legal action against the owners of the Sun, the defunct News of the World, and the Daily Mirror, in relation to alleged phone-hacking.
Documents have been filed on behalf of Prince Harry over the alleged illegal interception of voicemail messages, Buckingham Palace has confirmed.
His wife Meghan this week began legal action against the Mail on Sunday.
It is accused of unlawfully publishing a private letter to her father.
A spokeswoman for News Group Newspapers (NGN) - the publishers of the Sun and the News of The World - said: "We confirm that a claim has been issued by the Duke of Sussex."
The details of the duke's new legal action were first reported by the website Byline.
The BBC understands the duke's allegations against NGN predate 2010, but it is not yet clear when his claims against the Mirror date from.
A source at Reach, which owns the Mirror, told the Press Association it was aware proceedings had been issued but had not yet received them, so was unable to comment further.
Jonny Dymond, the BBC's royal correspondent, says the presumption is the legal action goes back to the phone-hacking scandal of the early 2000s.
What is the phone-hacking scandal?
Allegations of phone-hacking at the News of the World led to the closure of the tabloid in 2011 and an eight-month trial.
The story dates back to around 2007, when Clive Goodman, the then News of the World royal editor, and Glenn Mulcaire, a private investigator were convicted of intercepting voicemail messages left for royal aides and subsequently jailed.
The technique saw journalists hack into voicemail messages of celebrities by using a default factory-set Pin code and subsequently use the information to write news stories.
Princes William and Harry and the then Kate Middleton were all named among the victims in the 2011 trial, which led to a public inquiry.
One journalist pleaded guilty to phone-hacking at both the News of the World and the Sunday Mirror, while a judge in a civil trial against the Mirror ruled that phone-hacking at the paper was "widespread".
Between them, the two newspaper groups have paid out almost £500m to victims of phone-hacking in settlements and legal costs.
The duke's fresh legal claim comes just days after he accused the British tabloid press of "relentless propaganda" in his statement announcing his wife's legal action.
In the statement, which was issued during the couple's tour of southern Africa, Prince Harry said the "painful" impact of intrusive media coverage had forced them to take action.
Referring to his late mother Diana, Princess of Wales, the prince said his "deepest fear is history repeating itself".
"I've seen what happens when someone I love is commoditised to the point that they are no longer treated or seen as a real person," he said.
'Years of abuse'
Brian Cathcart, co-founder of Hacked Off, a campaign group which represents phone-hacking victims, told BBC News the move was a "measure of how far the couple have been pushed".
"For years and years the royals have been a free shot for the press," he said.
"This man has suffered very badly because of that - we know what happened to his mother."
He added: "I think we've moved on from the idea that celebrities are not entitled to privacy.
"The duke and duchess need to draw a line, they've had years of abuse."
The two newspaper groups could face a total bill for phone-hacking of up to £1bn, Hacked Off said earlier this year.
Dozens of celebrities have settled claims with the Mirror group, including actor Hugh Grant, while Sir Elton John, Elizabeth Hurley and Heather Mills settled claims against News Group Newspapers earlier this year.
Paul Connew, former deputy editor at the News of the World and the Sunday Mirror, told the BBC the duke was "determined to attack the popular press" in suing over "allegations which date back about 15 years."
Mr Connew suggested that the duke had launched the claim following "the rather over the top statement earlier this week attacking the press as a whole".
He added: "Prince William has a more mature take of the press and I expect that in the long run Prince Harry could come to regret this."
Media lawyer Mark Stephens said royals "rarely" take legal action because it can be a "high-risk strategy".
He told the BBC that the processes of legal disclosure of information between lawyers and then the royals being cross-examined could take them to "places they don't really want".
"So it is a high-risk strategy because things are outside their control.
"But it's also a high-risk strategy for the editors who are going to have to give evidence, too."