"There's so much the public doesn't know," Samantha Markle said in a new interview about her "graceful" half-sister Meghan

In a new interview on Monday, Meghan Markle‘s half-sister calls the Suits star “strong, very worldly, very educated, very graceful.”

Speaking to Good Morning Britain from her home in Florida on Monday, Samantha Markle said, “I think the British people and the world will be surprised. There’s so much the public doesn’t know. [They’ll be surprised] by how graceful and how lovely she is.”

Samantha, who is the daughter of Meghan’s father from his first marriage, denied that she and the actress are estranged. But a source previously told PEOPLE that Markle has no contact with her half-siblings and hasn’t for more than a decade.

While heaping praise on Meghan and her boyfriend Prince Harry — “they can bring so much to their role in global outreach, as a part of the royal family and in their humanitarian efforts” — Samantha also confirmed the less-than-flattering title of her proposed memoir: The Diary of Princess Pushy’s Sister.

“Well, it is true that I’m writing a book and the title is accurate, what is not true [is] this unbelievable swell that’s been created that it’s some sort of slamming ‘tell-all,’ ” she said.

“First of all, it’s only a tell-all in that I go through and recant some of the beautiful nuances of our lives, our family home. But more importantly it has to do with the inter-racial evolution of this country through the lens of my life and my family since the Civil Rights Act until present, and how that intersects with this recent event with my sister, you know, my feelings about it, my family’s feelings about it and how sad it was going through it all. But it’s more of a beautiful, warm, witty story of our lives and my life.”

Samantha says she doesn’t know if she’d get an invite to the wedding, should a royal engagement take place: “I’m quite a distance away, but of course I would go and yeah, I don’t know, but we’ll see.”