Royal watchers are told to prepare themselves for when Thomas Markle Jr. appears on "Big Brother VIP" because he has a lot to say about estranged sibling Meghan Markle.

The former window fitter has dirty secrets to spill about his half-sister. According to cast member Omarosa Manigault, he shared interesting things about the royal during the time they spent on the Australian reality TV show.

Calling him "quite the character," she said during an interview on The Kyle and Jackie O Show, "He talked a lot about his half-sister and I think that he needed to get a lot of that off of his chest."

Manigault, a former senior aide to Donald Trump, did not share any more details about what Thomas said about the Duchess of Sussex. But she hinted that it is bound to interest royal fans because they just let him talk, no holds barred.

Trailers released for "Big Brother VIP" hinted at Thomas revealing his famous sibling's secrets. He had called her "shallow" and unfit for Prince Harry. He claimed he had warned the royal about marrying his sister because she was going to ruin his life. He also talked about her first husband and how she just coldheartedly dumped him.

"The guy she was married to the first time, she just walked all over him and dumped him," he said of her ex-husband film producer Trevor Engelson and warned that the Duke of Sussex is "on the chopping block next."

Meghan Markle and Engelson were together for nine years. He had reportedly told Andrew Morton, author of "Meghan: A Hollywood Princess," that she made him feel "like a piece of something stuck to the bottom of her shoe" after their divorce.

Thomas Sr. recently also claimed that his daughter changed after she became an actress and married Prince Harry. She has disowned her family and he called it childish that she forbids him to see his grandchildren Archie and Lilibet. Fans will know more details about Meghan Markle's family, this time from her estranged sibling, when "Big Brother VIP" premieres on Monday, Nov. 1 on Channel 7.

Meghan Markle and her mother Doria Ragland
Meghan Markle and her mother Doria Ragland. Getty Images/Steve Parsons