The Duchess of Sussex has won the remainder of her copyright claim against the Mail on Sunday over the publication of a letter to her estranged father.
In February, Meghan won most of her claim for misuse of private information and copyright infringement.
But the newspaper had suggested she may not have been the sole copyright owner.
The duchess won her case after her former communications secretary denied co-writing the letter.
Associated Newspapers Limited (ANL) - the publisher of the Mail on Sunday and MailOnline - had previously argued the Duke and Duchess of Sussex's former communications secretary Jason Knauf was a co-author of the letter, meaning its copyright belonged to the Crown.
On Wednesday, the High Court heard that Mr Knauf has "emphatically" denied co-writing the letter to Thomas Markle. Through his lawyers, he said "it was the duchess's letter alone".
Ian Mill, representing the duchess, told the court that this "gives the lie" to the newspaper's suggestion that Meghan considered using the letter "as part of a media strategy".
The court also heard that lawyers representing "the Keeper of the Privy Purse, acting on behalf of Her Majesty the Queen" told Meghan's solicitors they "did not consider the Crown to be the copyright owner".
Launching their case against ANL in 2019, Prince Harry and Meghan said they were forced to take action against "relentless propaganda", with the duke saying he feared his wife would fall victim to "the same powerful forces" as his mother.
In the High Court in February, Lord Justice Warby ruled the publication of Meghan's handwritten letter to her father by the Mail on Sunday and MailOnline was "manifestly excessive and hence unlawful".
The judge said it was a "a personal and private letter" that dealt with the duchess's "feelings of anguish about her father's behaviour, as she saw it, and the resulting rift between them".
On Wednesday, Mr Mill acknowledged that Meghan had "shared a draft" of the letter with Harry and Mr Knauf "for support, as this was a deeply painful process that they had lived through with her".
"Mr Knauf was responsible for keeping the senior members of the royal household apprised of any public-facing issues, the media spectacle surrounding Mr Markle being one such issue," the barrister said.
The former communications secretary had "suggested that a reference to Mr Markle's ill-health be included", which Meghan added, but he "did not suggest any specific wording", the court heard.
His lawyers said he did not draft any part of the letter and "would never have asserted copyright over any of their content".
Mr Knauf, who is now chief executive of the Royal Foundation, set up by the Duke and Duchess of Cambridge, had said in a joint letter with other royal aides in January that he did not want to "take sides" in the legal dispute.
Andrew Caldecott, representing the publisher, said it was a "matter of regret" that Mr Knauf had not made clear he was not the author of the letter sooner.
He said as soon as ANL heard his account, the publisher indicated it would not oppose summary judgment in this case - meaning it could be resolved without going to trial.
But ANL is applying to the Court of Appeal for permission to appeal against the judge's February ruling on privacy and copyright, when the duchess won the bulk of her case.
An order that it must print a statement on its front page and page three that it infringed Meghan's copyright is on hold until the Court of Appeal's decision.
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