Jason Knauf, who was communications secretary to Meghan and Harry until March 2019, has said the handwritten letter to Thomas Markle was written with the “understanding” that it could be leaked to the media.
The new evidence comes as part of an appeal by the publisher of the Mail On Sunday Associated Newspapers Limited (ANL), which is challenging a High Court ruling that publishing extracts of the letter was unlawful.
ANL’s lawyers have asked to rely on Mr Knauf’s most recent statement in their legal bid to overturn the High Court’s decision to rule in Meghan’s favour without a trial.
On Wednesday, the statement was given to the media following an application by the PA news agency.
In his evidence, Mr Knauf said Meghan had “lost confidence” that the privacy of her communications with Mr Markle would be respected by him.
He continued: “The duchess said she was writing the letter in part to allow the duke to demonstrate to his family that some action was being taken by the couple to stop Mr Markle from continuing to engage with the media.
“She added that ‘…while unlikely perhaps it will also give my father a moment to pause’.”
Mr Knauf added: “She asked me to review the text of the letter, saying ‘obviously everything I have drafted is with the understanding that it could be leaked so I have been meticulous in my word choice but please do let me know if anything stands out for you as a liability’.”
The former aide also said that Meghan had queried whether she should call her father “daddy”, as she always had, in one of the messages the pair had exchanged over it.
Meghan said “in the unfortunate event that it leaked it would pull at the heartstrings,” according to Mr Knauf.
He later added that Meghan had “deliberately ended each page part way through a sentence so that no page could be falsely presented as the end of the letter”.
Mr Knauf later addressed the unauthorised biography of the Duke and Duchess of Sussex, Finding Freedom.
The former aide said the book was “discussed on a routine basis” and said it was discussed directly with Meghan multiple times.
Mr Knauf concluded that, as far as he was aware, neither Meghan nor Harry met with the authors of the book during his time as their communications secretary, and also he advised them not to engage directly with the authors.
He added: “She said she felt ‘fantastic’ after writing it and added that ‘And if he leaks it then that’s on his conscious (sic) but at least the world will know the truth.
“Words I could never voice publicly.”
Meghan later said she felt “fantastic” because the letter was “cathartic and real and honest and factual”.
In her written evidence to the Court of Appeal, Meghan denied she thought it likely that Mr Markle would leak the document, but had prepared for the possibility.
“To be clear, I did not want any of it to be published, and wanted to ensure that the risk of it being manipulated or misleadingly edited was minimised, were it to be exploited,” she said.
Mr Knauf was previously communications secretary to the Duke and Duchess of Cambridge and Prince Harry from February 2015 to May 2018.
After Harry and Meghan’s wedding in May 2018, Mr Knauf became communications secretary to both couples until March 2019.
Later that year he became the chief executive of the Cambridges’ Royal Foundation, a role he is due to step down from next month.
The Court of Appeal hearing in front of Sir Geoffrey Vos, Dame Victoria Sharp and Lord Justice Bean is due to end on Thursday with a judgment at a later date.