Once again, Thomas didn't hold back when it came to discussing his famous half-sister after the hosts asked about his upbringing with Meghan.
“I was 15 when she was born so I fed her, babysat just the normal family stuff, but I grew up in a divided home my parents split up when I was really young as well," Thomas explained, adding, "My Dad made sure people got together for the holidays and the important things."
Asked if he's ever had any correspondence with Prince Harry, Thomas revealed, “No, not me, my father did. My Dad doesn’t approve of him."
"My father says that he couldn’t even protect those chickens in their backyard if he needed to."
Watching on from the Big Brother house, housemates were shocked at the revelation, with Caitlyn Jenner quipping, "Well, this is going viral."
Thomas continued, “He wants Harry to do things proper, like call him up on the phone, go see him in person and say I want to take your daughter's hand in marriage.”
"He cherishes Meghan, he worships her, and I feel sorry for him in the fact that she won’t even pick up the phone and call my father and he’s just in the dark as much as everybody else is."
The jaw-dropping bombshells didn't stop there, however, with Fitzy and Wippa then quizzing Thomas about the infamous letter he penned Prince Harry.
WATCH: Meghan Markle's brother Thomas Markle Jr speaks out
“The reason I wrote that letter is because my private life went from private to in the paper," he explained.
"There were quite a few lies that were told about us, so I got a hold of the palace and I said could you please do something about the paparazzi.
"The response I got back was ‘distant family and I don’t know those people; that came from Meghan. So that kind of pissed me off and she knows damn well we had a great time growing up together, so I wrote that letter."
"She kind of knew when she was getting into it when she went into it. If you got a job and you got paid 4 million dollars a year salary to go bow and curtsey and take pictures and do some charity work here, some charity work there, I mean that’s about the highest pedestal you can get to. Do your job and not gripe about it.”
He added of the pair's bombshell interview with Oprah, "I don’t 100% buy that and I don’t agree with some of the things on the Oprah interview as far as not having those services available. I can’t imagine being that sheltered?"
“Everybody’s always loved Meghan, everybody’s always supported her no matter what. I have I mean I may say bad things about her, I may write horrible letters to people, but the end result is that I do love my sister.”