Lawyers defending the Mail on Sunday against a breach of privacy action brought by Meghan Markle, the Duchess of Sussex for its publication of a letter she wrote to her father are scouring new royal tell-all book Finding Freedom for information that may refute her claims.

Finding Freedom, the unofficial biography detailing Markle and Prince Harry's royal exit, names the couple as sources. The pair has denied any involvement.

According to The Telegraph, Omid Scobie and Carolyn Durand wrote in the authors' notes at the back of the book that they spoke with friends, aides and past or present staff members of Prince Harry and Markle. The authors also spoke to "the couple themselves," the notes say.

Finding Freedom may help the Mail on Sunday prove that the duchess gave her friends permission to speak to the news media anonymously in a bid to put her side of stories. The lawyers may call Markle to give evidence in the newspaper's response to her charges.

Naming Harry and Markle as "sources" for Finding Freedom could be considered a "confession," according to lawyer Mark Stephens. He says it is almost an admission they authorized this book. It gives the respondents an opportunity to question Markle.

The Mail on Sunday says the contents of the letter at the heart of Markle's privacy action were first discussed by her friends in a People Magazine interview. Markle has claimed she was unaware her friends would talk to the news media.

But Scobie said on Good Morning America that Markle wanted the letter to be public. She wrote the letter to her father "with the public in mind" because the duchess knew it would be released to the tabloids.

Prior to the publication of Finding Freedom a representative for Harry and Markle said they didn't collaborate or sit down for an interview with the book's authors.

Scobie defended the book on Twitter. He said he "exchanged a few words" with Harry and Markle during official royal tours but didn't formally interview them.