Older sister Markle, who has a father with the Duchess of Sussex, first sued Meghan in 2022 because the former royal worker was featured in the Netflix documentary series Oprah Winfrey and Harry and Meghan.

Samantha’s civil suit claimed the comments were “despicable, hurtful and false” statements that suggested she was “a foreigner, a liar and a … deceitful, fame-seeking impostor with mean intentions.”

In response, Meghan’s lawyers argued that the Duchess of Sussex’s views are protected by the First Amendment.

“An implied or express statement that (Samantha) belongs to a hate group that spreads misinformation about Meghan is an opinion protected by the First Amendment,” Meghan’s lawyers wrote in court documents.

Meghan won the original case, but Samantha took the case to the 11th Circuit Court of Appeals.

In a new court filing for the appeal seen by Newsweek, Samantha’s lawyer, Peter Ticktin, argued that Samantha “undoubtedly” suffered as a result of her famous brother’s documentary.

“There can be no doubt that Meghan Markle verbally attacked her sister Samantha Markle in her documentary,” Mr Ticktin said.

The lawyer wrote that Samantha, who is confined to a wheelchair, was “forced to relocate” and “faced realistic death threats”, possibly from supporters in Sussex.

Samantha’s case is understood to be based on a particular scene in the Netflix show in which Harry and Meghan’s friend, tech entrepreneur Christopher Bouzy, described the “trolling” the Duchess of Sussex received.

“This is not your everyday trolling. It’s crazy. And it was done by people who just weren’t typical unquote trolls,” Mr. Bouzy said.

“These are housewives, these are middle-aged Caucasian women.

“Samantha Markle was part of the group that spread a lot of this misinformation.”

The segment ended with an emotional Meghan saying: “You make people want to kill me. It’s not just a tabloid. It’s not just a story. You scare me.”

Mr Ticktin claimed that Samantha “never” trolled Meghan and complained that the glamorous duchess was “allowed to walk away” from the allegations.

“(Samantha) has never been part of a group that spread misinformation, never trolled Meghan, never been part of a hate group, never used the N-word on tweets, never monetized no hate tweets against Meghan or did anything to make anyone who wants to kill Meghan or get upset about such activity,” he said.

“However, with a dismissal, Meghan is allowed to walk away as if she is innocent.”