In an upcoming interview, Meghan Markle's half-sister, Samantha Markle, claims that the Duchess and Prince Harry have a "toxic relationship." Samantha is set to join her father and brother for what is being called their "last ever interview" just one week before King Charles' Coronation.

In an exclusive, the family members will speak with Channel 7's Taylor Auerbach, sharing never-before-seen family videos and a surprising message. A teaser clip for the interview, which is scheduled to air on Sunday, features Samantha's thoughts on her half-sister's relationship.

Samantha states, "They're really unhealthy for each other, it's a toxic relationship," as a video of Meghan and Harry holding hands plays in the background. Nevertheless, the couple has always seemed united since they began dating in 2016. They had a fairy-tale wedding in 2018 and currently reside in Montecito, California, with their two children, Prince Archie and Princess Lilibet.

Broadcaster Taylor Auerbach announced the Markle family interview on Twitter, sharing a dramatic trailer. He wrote, "WORLD EXCLUSIVE: This Sunday on ⁦@7NewsSpotlight - Meghan Markle as you've never seen her before. For the first time, the Markles unite with an extraordinary message on the eve King Charles III’s coronation. These hidden tapes will stun the world! Only on ⁦@Channel7."

The teaser begins with footage of Meghan in a convertible, wearing a tiara and prom dress, as a voiceover states, "The world has never seen Meghan like this, the homecoming queen." The clip transitions to Taylor speaking with the Markle family, saying, "This will be your last interview ever." The voiceover promises, "Treasured memories, home truths, and secret tapes are all coming out."

Samantha claims in the interview, "She would still be a waitress if it wasn't for dad." Meghan's brother, Thomas Markle Jr., adds, "We're not going to go away. This is going to change everything."

Thomas Markle, Meghan's father, passionately pleads with his daughter in the interview, asking, "How can I fix this?" The much-anticipated interview is set to premiere on Channel 7's Spotlight on Sunday, just before King Charles' Coronation.