The Mail On Sunday must publish a front-page statement about the Duchess of Sussex's victory in her copyright action against the newspaper, the High Court in London has ruled.
Meghan Markle won her privacy claim against the newspaper last month over the publication of a "personal and private" handwritten letter to her estranged father.
Ms Markle had sued Associated Newspapers Limited (ANL), the publisher of The Mail On Sunday and MailOnline, over a series of articles which reproduced parts of the letter sent to 76-year-old Thomas Markle in August 2018.
Lord Justice Warby ordered that, on a single occasion, the front page of The Mail On Sunday will have to carry a statement saying that Ms Markle has won her claim for copyright infringement against ANL.
The same edition will have to state on page three that, following a hearing in January, the High Court gave judgment for the duchess on her claim for copyright infringement.
It will also have to include the following statement: "The court found that Associated Newspapers infringed her copyright by publishing extracts of her handwritten letter to her father in The Mail On Sunday and in MailOnline.
"There will be a trial of the remedies to which the duchess is entitled, at which the court will decide whether the duchess is the exclusive owner of copyright in all parts of the letter, or whether any other person owns a share."
The judge said the notice must also be run on MailOnline for one week, with a link to the court's full ruling on Ms Markle's victory, which was delivered in February.
He added: "In my judgment these are measured incursions into the defendant's freedom to decide what it publishes and does not publish, that are justified in pursuit of the legitimate aim I have identified, and proportionate to that aim.
"They will involve little if any additional expense, and certainly nothing approaching the scale of the expense that has been lavished on this litigation."
The court ruling comes as the Duchess of Sussex said it feels "liberating" to be able to speak out about her life in the British royal family in a new excerpt of her hotly anticipated interview with US host Oprah Winfrey.
Ms Markle married Britain's Prince Harry in 2018. The couple now reside in Los Angeles with their son Archie and are expecting their second child.
They stepped down from frontline royal duties last year, in part blaming media intrusion for their decision to move to America.
The interview will be shown on RTÉ2 on Monday, 8 March, at 9.30pm.