The complaint, reportedly made in October 2018, allegedly claimed Meghan "drove two personal assistants out of the household and was undermining the confidence of a third staff member," and in a statement last Wednesday, Buckingham Palace said they were "concerned" about the claim and would investigate.
Asked if Harry and Meghan have been stung by leaks from royal aides and family questioning the duchess' credibility, a friend of the couple tells ET, "they are disappointed, and it is a sad reality that these leaks have followed them for some time."
As for the accusations of bullying, the friend claims "the timing was purposely intended to hurt Meg." Meghan and Harry's are expected to tell all in a sit-down interview with Oprah Winfrey on Sunday.
As the couple's friend says, Meghan and Harry are "happy that they will finally be able to set the record straight."
In a statement to ET last week, a spokesperson for the pair also noted the timing of the bullying allegation.
"It’s no coincidence that distorted several-year-old accusations aimed at undermining the duchess are being briefed to the British media shortly before she and the duke are due to speak openly and honestly about their experience of recent years," the statement said.
"The duchess is saddened by this latest attack on her character, particularly as someone who has been the target of bullying herself and is deeply committed to supporting those who have experienced pain and trauma," the statement continued. "She is determined to continue her work building compassion around the world and will keep striving to set an example for doing what is right and doing what is good."