The Duchess of Sussex has said she is not afraid of the consequences of speaking out in her and Prince Harry's interview with Oprah Winfrey.
In a second teaser clip released by CBS for the upcoming interview, Meghan said "a lot... has been lost already".
She said she could not be expected to be silent if the royals had a part in "perpetuating falsehoods about us".
It comes as Buckingham Palace said it had launched an investigation into claims the duchess bullied royal staff.
The interview with Winfrey, which will air in the US on Sunday, is expected to lift the lid on Harry and Meghan's short period as working royals together before they stepped down for a life in the US.
In the 30-second teaser clip, Winfrey asks the duchess: "How do you feel about the palace hearing you speak your truth today?"
She replies: "I don't know how they could expect that, after all of this time, we would still just be silent if there is an active role that The Firm is playing in perpetuating falsehoods about us.
"And, if that comes with risk of losing things, I mean, I ... there is a lot that has been lost already."
'Attack on her character'
Past and present royal employees are to be invited to speak in confidence about their experiences of working for Meghan as part of the palace's investigation.
It follows a report in the Times newspaper that the duchess faced a bullying complaint when she was a working royal.
According to the story in the Times, the complaint was made in October 2018, while the duke and duchess were living at Kensington Palace.
A leaked email sent from a staff member, which was published by the newspaper, alleges that Meghan drove two personal assistants out of the household. The report claims she undermined the confidence of a third member of staff.
In a statement, Buckingham Palace - which is responsible for the hiring of royal staff - said it was "clearly very concerned about allegations in the Times" and its HR team would look into the circumstances outlined in the article.
"The Royal Household has had a Dignity at Work policy in place for a number of years and does not and will not tolerate bullying or harassment in the workplace."
An earlier statement issued by Meghan's spokesman 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.
"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."