Meghan Markle’s estranged half-brother has revealed he is writing a tell-all book about the Duchess of Sussex’s childhood.

Thomas Markle Jr., 58, is writing the book in the tranquility of the Philippines, where he is supporting his and Meghan’s father, Thomas Markle Sr., 80.

‘When my book is finished, ooh it’ll be swooped up real quick ’cause it’s getting there,’ Markle Jr. told the Mirror.

‘I’m working on it. It’s coming out,’ he said, vowing that ‘it’s gonna be good.’

Markle Jr. even expects his book about his half-sister will spin off into other productions.

‘I really want to spin off the book, then when the book gets read, the documentary will follow,’ he said.

‘I’m not a greedy person, it’s not about the money – it’s about the principle,’ Markle Jr. claimed, though he also admitted ‘it would be nice to have a nice little cushion from selling a book.’

He also claimed that ‘everyone wants the book,’ and he now has time to write it, as he cares for their mobility-impaired father on the island of Cebu – more than 7,000 miles away from the Duchess of Sussex, 43, and Prince Harry, 40, as well as their two young children, ages six and three.

Thomas Markle Jr., 58, is writing a tell-all book about the Duchess of Sussex’s childhood

Markle Jr. has been highly critical of his half sister, Meghan Markle, in the past. She is pictured here with her husband, Prince Harry

Markle Jr. has been highly critical of his half sister in the past, accusing her of telling ‘malarkey’ stories about her childhood on her new Netflix series With Love, Meghan.

‘This is probably the first time I felt sorry and embarrassed for her’, he told journalist Kevin O’Sullivan in March.

When he was then asked whether his father had watched the show, 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.’

On the show, the Duchess of Sussex called herself a ‘latchkey kid’ who ‘grew up with a lot of fast food and TV tray dinners.’

She had also previously claimed that she ‘grew up on the $4.99 salad bar at Sizzler’ and how her family was poor in an letter to US politicians, asking them to consider her plea for paid leave for parents.

But on her claims that she grew up poor, Markle Jr said: ‘That’s just another one of the malarkey stories she sold to the Royal Family for sympathy. We weren’t poor. She didn’t have to rub two nickels together at Sizzler’s salad bar.’

Critics have previously pointed out that Meghan was raised in middle class comfort in the California suburb of Woodland Hills in a home Thomas Markle, an Emmy-award winning lighting director, bought shortly before Meghan was born in 1981.

He sent her to Hollywood’s private Little Red Schoolhouse, whose old students include Elizabeth Taylor and Judy Garland, where staff feed students six different types of organic vegetables from the school garden each week.

When Meghan was nine he won $750,000 in a lottery and the money helped send Meghan to the $16,000-a-year Immaculate Heart Catholic School, one of LA’s finest.

Markle Jr is writing the book from the Philippines, where he is taking care of his and Meghan’s 80-year-old father (pictured)

In fact, in a blog post from the Duchess of Sussex’s now-defunct website The Tig revealed the affection that she once held for her ‘hardworking daddy’ before he was shut out of her life in 2018.

It is now believed that their relationship first became strained when he posed for paparazzi photographs prior to Meghan’s royal wedding in 2018.

The 80-year-old also suffered a heart attack just before the ceremony, preventing him from walking his daughter down the aisle.

He has never met his grandchildren, but when his discussing his move to Southeast Asia in January, he said he is ‘not running away’ and is instead ‘going in search of a more positive life.

‘Every day I see something about Meghan,’ Markle Sr. lamented. ‘I wish her no ill will.

‘My dream is that one day I could bring my whole family together, like a “normal” family,’ he admitted.