Meghan said she is close friends with Samantha Markle's biological daughter, Ashleigh.
Meghan said she couldn't invite Ashleigh to her wedding because of her association with Samantha.
Samantha has been openly critical of Meghan since she started dating Prince Harry in 2016.
Meghan Markle said she was told she couldn't invite one of her closest friends - Samantha Markle's biological daughter - to her wedding in 2018.
Speaking in episode three of the Netflix docuseries, "Harry and Meghan," which aired on Thursday, the duchess shared details about her relationship with her estranged sister Samantha as well as her niece, Ashleigh Hale.
Hale is the daughter of Samantha Markle, Meghan's estranged half-sister who has been openly critical of the duchess since she started dating Prince Harry in 2016. Samantha published a book about Meghan, titled "The Diary of Princess Pushy's Sister," in February 2021.
"Suddenly it felt like she was everywhere. I don't know your middle name, I don't know your birthday. You're telling these people that you raised me, and you've coined me 'Princess pushy?'" Meghan of Samantha's interactions with the media.
In a statement shared in the docuseries, Samantha said that the "media fabricated quotes that have been attributed to her." Samantha Markle did not immediately respond to Insider's request for comment.
Also speaking in the docuseries, Samantha's daughter Hale said she was raised by her grandparents on her father's side, who got custody of her when she was 2. She said she reconnected with Samantha in 2007 after not having seen her since she was 6 years old.
Shortly after Samantha and Hale reconnected, Meghan said she got in touch with Hale via email. They "hit it off," according to Meghan, who said they became close and went on vacations together.
"I think she takes on a lot of roles for me. There's a sister element, she's maternal, she's a best friend," Hale said.
Hale said that after Meghan and Harry started dating, Samantha started speaking to her about Meghan in a resentful and angry way, which she said caused her and Samantha to stop talking completely.
Even so, Meghan said that she was advised by the palace's press team that she couldn't invite Hale to the royal wedding in May 2018 as it would be difficult to explain why Hale was invited and Samantha wasn't.
"I was in the car with H, and I called her and I had her on speaker phone and we talked her through the guidance we were given and why this assessment was made. And that's painful," Meghan said.
"I think I said I was hurt on some level, but I understand where it was coming from," Hale said. "To know that it was because of my biological mother, that this relationship that's so important to me was impacted in that way. To feel like because of her it was taken away was hard."
Buckingham Palace, Kensington Palace, and representatives for the Duke and Duchess of Sussex did not immediately respond to Insider's request for comment.