Samantha Markle supposedly gave palace officials an "ultimatum" in which she'd only visit with her sister if they didn't arrange a meeting.
According to the Daily Mirror, the 53-year-old had flown to the United Kingdom "to confront her younger sibling" after sending another letter to Kensington Palace warning that her behaviour would "escalate" unless such a meeting was scheduled.
Likewise, a source tells ET that on Oct 1st Samantha and boyfriend Mark Phillips were seen outside Kensington Palace.
According to the newspaper, the 53-year-old argued with police guarding the palace gates before handing over a letter for her sibling.
Samantha, who is confined to a wheelchair due to multiple sclerosis, was accompanied by her partner.
However, it's believed that she was turned away from security, more on that here, and since then she's been sharing her thoughts about the whole situation on social media.
Samantha, Meghan's half sister from her father's first marriage, has previously called the royal "cold" and fake. "It was a sad sight". One source said: "It really hit home for her just how loved Meghan and Harry are".
Since her visit, Samantha Markle has posted a series of tweets about the trip to London, including a sarcastic post featuring a clip from Monty Python.
But in a recent interview with TV personality and journalist Jeremy Vine, Samantha apologized for her remarks over the past few months.
"I just think that families can be this way when there's confusion and when people are hurt".
Samantha went on to reply to another commenter on Twitter, saying that Meghan ghosted "everyone" in the family, especially Thomas and this is why she spoke out.
"Moving forward, I apologize and wish things could be different", Grant said.