In the explosive trailer for the show, the 55-year-old claimed he warned Harry about Meghan.
He said: “I told Prince Harry she’d ruin your life.
“She’s very shallow.”
Meghan’s estranged brother said he does not have a relationship with his younger sister and was not invited to the royal wedding in 2018.
Before the wedding, he had not seen the former Suits actress for around seven years.
The window fitter has previously criticised his half-sister in the press and described her as “phoney” and a “jaded, shallow, conceited woman”.
He also lashed out at the Duchess for snubbing their father, Thomas Markle Sr, after he was caught collaborating with US paparazzi.
Meghan said she and Harry were told Mr Markle was due to publish contents of a private letter to the press days before their 2018 wedding.
She claimed her father denied talking to the press and he said he had not leaked the contents of the letter to the press.
Meghan told Oprah: “If we are going to use the betrayal, it’s because when I asked him, when the comms team told us this the story was coming out, we called my dad and I asked him and he said, ‘No, absolutely not’.”
Meghan is not only estranged from her father and half-brother but also her half-sister, Samantha Markle, who has previously hit out at the Duchess.
Ms Markle said: “She would have to apologise – a public apology, god, I know would be like getting blood from a rock but she did a lot of public damage.
“Really, I mean I really feel like this thing was all orchestrated that she needs to unravel the damage.”
Meghan’s estranged half-sister said the Duchess has to make the “first move” and to apologise to her father who gave her an “incredible life”.
In March, Ms Markle told TMZ: “She did a lot of damage to a man who gave her an incredible life – so hurtful, so wrong.
“She would need to make the first move and, I mean, you know, parents are always unconditionally loving but god, she really hurt him.”
Elsewhere in the explosive interview, Meghan made several remarks about her half-sister and claimed her sister changed her surname back to ‘Markle’ following her wedding to Prince Harry.
But her estranged sibling claimed this accusation was inaccurate and said ‘Markle’ has always been her name.
She continued: “I was a Markle before she was. I thought that was kind of weird that she would say I only changed my name back when she met Harry. Markle has always been my name.”
Source: EXPRESS CO UK