The trial focused on Meghan's allegations against Associated Newspapers was scheduled to start on January 11 and last approximately 10 days. However, that date has now been "vacated" and a new trial date is being arranged for autumn 2021. During today's hearing, which has been conducted remotely, Mr Justice Warby said he had conducted earlier today a private hearing from which the press and public were excluded.
Upon ruling on the postponement, he said: "The right decision in all the circumstances is to grant the application to adjourn.
"That means that the trial date of January 11 2021 will be vacated and the trial will be refixed for a new date in the autumn."
The High Court judge also said the "primary basis" on which the adjournment was sought was "a confidential ground".
It was announced yesterday Meghan's lawyers were seeking a summary judgement.
The Duchess of Sussex's representatives are still going to apply for it, as reported by ITV's royal editor Chris Ship.
Meghan Markle's request to delay the privacy case trial has been approved by a judge
He wrote on Twitter: "Meghan is STILL going to apply for a summary judgement so that even the delayed trial is not required as she claims the Mail on Sunday has 'no real prospect' of defending its actions in law."
A decision on the summary judgement won't be taken today, Mr Ship added.
This morning, the judge also heard Meghan's application for permission to appeal against a decision taken at the latest skirmish lost by Meghan, during which Judge Francesca Kaye allowed Associated Newspapers to rely on the biography Finding Freedom in its defence.
Jane Phillips, representing Meghan, told Mr Justice Warby: "The new case ought not to have been allowed.
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"It was speculative, it was unsubstantiated by evidence and it was inherently implausible and, we say most importantly, it was bad in law."
She added that the new case was "not only a stab in the dark, but it was a stab in the dark in the wrong room".
Today's ruling took place instead of another hearing previously scheduled to be held by Judge Kaye at 11am.
Judge Kaye was due to consider costs and case management issues ahead of the trial.
Meghan is suing the publisher of the Mail on Sunday, Daily Mail and MailOnline - Associated Newspapers - over the publication of extracts of a private hand-written letter she sent to her estranged father.
The Duchess of Sussex had sent this letter to Thomas Markle Snr in August 2018.
The articles including extracts from it were released in February 2019.
Meghan is seeking damages from the publisher, accused of alleged misuse of private information, copyright infringement and breach of the Data Protection Act.
Associated Newspapers wholly denies Meghan's allegations, particularly the Duchess's claim that the letter was edited in any way that changed its meaning, and has said it will hotly contest the case.
Today's hearing follows other skirmishes - two of which have been lost by the Duchess of Sussex.
In May, Associated Newspapers got removed from the case allegations its publications had acted dishonestly and stoked the rift between Meghan and her father.
In August, Meghan's request to keep a secret the identity of her five friends who, in early 2019, had spoken to People magazine was welcomed by the court.
During their interview, these friends briefly mentioned Meghan's letter to her father.
Last month, Meghan lost another skirmish, with the judge ruling in favour of Associated Newspapers who had asked for the right to use the unofficial biography of the Sussexes, Finding Freedom, during the trial.
Meghan's lawsuit was first announced by Prince Harry in October last year, as their successful tour to South Africa was about to end.
The Duke published a blistering statement on a website, SussexOfficial.uk, in which he said Meghan had "become one of the latest victims of a British tabloid press that wages campaigns against individuals with no thought to consequences."
Harry added, recalling his mother Princess Diana's relationship with the press: "Though this action may not be the safe one, it is the right one.
"Because my 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.
"I lost my mother and now I watch my wife falling victim to the same powerful forces."