The length of her stay in the United Kingdom is unknown, but it is thought that she intends to confront Meghan, 36, over their father's ill-health.
"I would just say that there's so much water under the bridge and so much has been out of control that was never meant to", she began.
After the 74-year-old was exposed, he reportedly had a heart attack and did not attend his daughter's wedding. "I don't care whether she is p***** off at me or not".
Despite Ms Markle's apparent determination to see Meghan, her friends believe the Duchess will not see her half-sister.
Sources have revealed to the Daily Mail, however, that Meghan would never entertain the idea of a showdown with her half sister.
Prince Harry joined his brother Prince William as a married man after wedding Meghan Markle in May.
Earlier this month, Samantha went on a furious social media tirade about her sister and her new husband.
"Happy Birthday Harry! As you "Mack down" on your birthday cake, think about the birthday wishes you never extended to your FATHER-IN-LAW." she wrote on Twitter.
Elon Musk to Resign as Chair of Tesla Board but Remain CEO
As part of a settlement of charges that Mr Musk misled investors, he will no longer sit at the head of the boardroom table. Tesla did not immediately respond to a request for comment and Musk could not immediately be reached for comment.
Cardi B Turns Herself In For Alleged Involvement In Strip Club Assault
Cardi B is expected to turn herself in to police Monday in connection to a fight at a Queens strip club, a police source said. A source close to the artist says the alleged incident was "spontaneous", and only started after someone threw a drink.
Molinari: British Open champ, now Ryder Cup hero
Woods' record in Ryder Cup matches is now 13-21-3 - an abysmal record for a player who has enjoyed so much individual success. Johnson went from 1 up to 2 down in a four-hole stretch that ended his chances.
However if she is hoping to run into her royal sister in London, she won't have much luck on Wednesday as the Duke and Duchess are visiting Sussex for the first time since receiving their titles.
In a separate post, she fumed: 'I am not candy coating anything anymore! "The DUCHASS should be humane to our father who has given her everything and this media crap can stop!"
She added: "The goal at that point wasn't just getting closer".
Though Samantha acknowledged that Meghan was certainly hurt by the comments, Samantha continuously claimed that "reality has been twisted".
When it came to the paparazzi photos, Samantha alleged that she came up with the idea after the press made him "look like a disgusting slob".
Since Meghan became a royal, Ms Markle has hit out at her for being "cold", accused her of ignoring her father, branded Harry a "wuss", and has gone as far as to say she would blame Meghan should Thomas Markle die.
"There's no way she can have a relationship with him or even reach out to him to stop him from speaking".
'And as far as her dad's health is concerned, Meghan is not anxious. She knows he'll record the conversation and sell it.