Ms Markle hit out at her sibling on Twitter after Meghan’s bombshell letter to her father Thomas Markle was revealed on Sunday. In the note – which was written last August – Meghan insisted that she “barely knows” her half-sister, adding that she has told “vicious lies”. Meghan wrote to her father: “I pleaded with you to stop reading the tabloids.
“On a daily basis you fixated and clicked on the lies they were writing about me, especially those manufactured by your other daughter, who I barely know.
“You watched me silently suffer at the hands of her vicious lies, I crumbled inside.”
But Ms Markle – who is penning two tell-all books about Meghan set for release later this year – took to social media to rant about her half-sister.
She wrote: “Some narcissists were “only children” , others,.., wish they were.”
Meghan’s half-sister added: “If I had 600 mill she would care.”
Ms Markle, who lives in Florida, also clashed with one of Meghan’s fans who accused her of changing her surname to “cash in”.
The 54-year-old responded: “My name has never legally been Grant so chew on that for a while. Oh and stop reading tabloids you’re totally misguided.”
In a second post, she said: “Actually my name was Markle from birth my last name Markle is on my degrees and Grant was only a pen name to protect my address. Markle is my maiden name..I had it since 1964.”
Meghan’s long-running family row took another turn last week after five of the duchess’s friends spoke out to defend her in an extraordinary interview with US magazine People.
The duchess’s anonymous pals revealed that she had written to Mr Markle following the royal wedding fallout.
Referring to Meghan’s half-sister and her half-brother Thomas Markle Jr, one of the duchess’s unnamed friends said: “They have been made to appear as siblings who had this falling out, and that’s not the truth at all. They were not a part of her life.”
Another insider recently revealed that Meghan burst into tears when she found out about Ms Markle’s plans to publish a book about her.
The source told the Daily Mail: “She stopped reading things after finding out about her sister’s book. She cried when she found out about it.
“Out of everything that’s been said, the one thing that really upset her was that.
“She and Samantha never had a very good relationship and she feels her sister is using her position for profit.”
Ms Markle is set to release her first book – titled In The Shadows Of The Duchess – in April, around the time Meghan is due to give birth to her first child with Prince Harry, while the second part will be published in July.