Meghan Markle filed a formal complaint with British broadcaster ITV, after presenter Piers Morgan criticised her claims against the royal family and later quit.
Mr Morgan left his role as host of Good Morning Britain yesterday following a scathing attack on the Duchess of Sussex's interview with US chat show host Oprah Winfrey.
She and her husband, Prince Harry, accused the royal family of racism, while the former television actress said she had suicidal thoughts during her time in Britain.
Former CNN host Mr Morgan's comments that he did not believe her sparked 41,000 complaints to Britain's broadcasting regulator Ofcom.
The Press Association news agency said it understood Meghan formally complained to ITV before he resigned, confirming a report in the Daily Telegraph newspaper.
The complaint focused on how his remarks may affect those trying to deal with their own mental health problems, it added.
It did not concern his repeated criticism of her or allegations of racism, which have rocked the monarchy.
Meanwhile, the executive director of an industry body for the UK press has resigned following a row over its reaction to comments made by the Duke and Duchess of Sussex about racism in the media.
Ian Murray, executive director of the Society of Editors, said he would step down from his role so the organisation can "rebuild its reputation".
A strongly-worded statement issued by the body following Harry and Meghan's interview with Oprah Winfrey said it was "not acceptable" for the couple to make claims of racism in the press "without supporting evidence", adding that the press in the UK press was not racist.
"Since the statement was issued the SoE has been heavily criticised," Mr Murray said.
"While I do not agree that the Society's statement was in any way intended to defend racism, I accept it could have been much clearer in its condemnation of bigotry and has clearly caused upset.
"As executive director I lead the Society and as such must take the blame and so I have decided it is best for the board and membership that I step aside so that the organisation can start to rebuild its reputation."
He added that the original statement was "not intended to gloss over the fact the media industry in the UK does have work to do on inclusivity and diversity".
The editors of the Guardian and HuffPost UK previously issued statements saying they did not agree with the Society of Editor's position.
Piers Morgan vows he will be back
Piers Morgan quits Good Morning Britain
Mr Morgan, a former tabloid newspaper editor, has been a consistent critic of Meghan after she cut off contact with him after she met Harry and they married in 2018.
Yesterday, Mr Morgan stormed off the set of Good Morning Britain as he clashed with a fellow presenter who defended the duchess.
In a tweet as the programme aired this morning, Morgan said he stood by his remarks and said he would fight for freedom of speech.
"On Monday, I said I didn't believe Meghan Markle in her Oprah interview. I've had time to reflect on this opinion, and I still don't," he wrote.
Buckingham Palace yesterday responded to the explosive claims.
Queen Elizabeth II said Meghan and Harry, who quit royal life last year, and their son Archie would remain "much-loved family members".
But she also said the accusations would be dealt with "privately".
Asked to respond to Buckingham Palace's statement, a spokesman for Meghan and Harry said they would not be commenting any further.
Additional reporting PA
