Related : Meghan Markle's Family Is Still Talking About Her

The idea of "turning your back" sustained itself in a third tweet on Saturday. "turn your backs to people on a Christmas card is rude," she wrote. "if you want to be private you don't do it on a Christmas card but the world sees. That's like saying merry Christmas look at my butt."

Samantha's negative words about Meghan and the royals are not new. Attempts at extending an olive branch have been few and far between as well.

In October, Samantha flew to London and tried getting into Kensington Palace to deliver a letter to the Duchess, but she was subsequently turned away by palace security. She said in an interview on Oct. 1, "I've always wanted to see London, but really I wanted to make the trip and sort of speak the wishes and thoughts and sentiments of my father, and hopefully get a message to my sister."

She continued, "I was hoping maybe we would have the chance to speak—that she would know I was here. But I don't think that's going to happen."

A few weeks later, Samantha apologized for any "past tension" but then called Meghan a "liar" after she gave a speech in Fiji on her royal tour of the South Pacific.