Meghan Markle is set to face a new challenge as her half-brother, Thomas Markle Jnr, has confirmed that he is writing a tell-all book about the Duchess and her childhood. Speaking from the Philippines, where he has relocated with his father, Thomas Markle Snr, he vowed that the book is "gonna be good."

In an interview with the Mirror, Thomas said: "When my book is finished, ooh it'll be swooped up real quick cause it's getting there. I'm working on it. It's coming out. It's gonna be good."

In what will surely come as a further worry to the Duchess, her estranged half-brother added: "I really want to spin off the book, then when the book gets read, the documentary will follow," he said.

Thomas went on: "I'm not a greedy person, it's not about the money - it's about the principle." However, he went on to add: "It would be nice to have a nice little cushion from selling a book."

Markle Jr. has been hugely critical of his half-sister in the past and has claimed that she has told "malarkey" stories about her childhood on her lifestyle Netflix series, With Love, Meghan.

On his view of the series, he told journalist Kevin O’Sullivan back in March: "This is probably the first time I felt sorry and embarrassed for her". He was then asked whether his father had watched his daughter's show, to which Markle Jr replied: "I didn’t have enough heart medication for him to watch it. I didn’t want him to kick the bucket, so I’d have to go refill the prescription before I let him watch it."