Meghan Markle's half-sister reportedly clashed with security as she turned up at Kensington Palace to confront the royal.
Samantha and her partner were then photographed handing a note to the guard before they left the premises and were spotted buying Harry and Meghan masks nearby.
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".
Samantha Markle wanted to speak with her sister, Meghan, about the health of their father, Thomas.More news: Complete schedule for 2018 ALCS between Astros-Red Sox
According to the Daily Mail, Samantha Markle took things to the next level by showing up to Kensington Palace in person.
She said she and her father Thomas would still have been hurt and not being invited to the star's wedding to Prince Harry, but the situation wouldn't have "snowballed". He has apologized for the images and issued public pleas to reconcile with Meghan.
Samantha, 53, flew into the United Kingdom with the aim of confronting her half-sister but pictures appear to show her being met with a wall of silence after an embarrassing stand-off with palace security.
Samantha said that if she got the chance to speak to Meghan, she would tell her it's "water under the bridge" and recognize that their issues spiraled "out of control".
One of her tweets said that the "Duchess should bow to the daddy" presumably implying that Meghan should bow to their father and we're not sure where on earth she's going with this, it does seem weird (although she is, of course, entitled to her opinion). "Dad only spoke out because he was being ignored and disregarded", she wrote in part to another Twitter user.