The 34-year-old Duke and 37-year-old Duchess of Sussex's tour is set to take place from Tuesday, October 16th, until Wednesday, October 21st.
Meghan Markle isn't phased by her half-sister's recent unexpected visit.
Samantha first hit out at her famous half-sister after her romance with Prince Harry was revealed, branding her a "social climber" who is "not fit to be a royal". Until now, Megan and Harry were living in the small Nottingham cottage with two bedrooms, located in the Kensington Palace.
Coral's Harry Aitkenhead had said: "It's Prince Harry's 34th birthday this weekend and with the couple making no secret of their desire to start a family, we think that it's nearly inevitable now that the latest Royal baby will be arriving in 2019".
But despite being told to get lost, Samantha was captured handing palace guards a letter which many believed is addressed to Meghan.
"Everybody would love to know what's in that letter", Samantha tweeted on Sunday.
In the end, Samantha Grant, who came to the Palace in a wheelchair (she suffers from multiple sclerosis) accompanied by an unknown man in the Palace is not allowed.
She said: "I just think that families can be this way when there's confusion and when people are hurt".
"I felt it could've all been nipped in the bud had everyone been included and we all agreed to move forward with positive resolve".
"She explained she had been in touch with palace officials and claimed they had ignored her advances, leaving her no choice but to arrive uninvited". "My sister and the Royals handled things wrong and everybody knows it", she wrote.