Duchess Meghan says she has no relationship with her half-sister Samantha Markle.

The Duchess of Sussex

The Duchess of Sussex

The Duchess of Sussex revealed during an unaired clip from her and her husband Prince Harry's tell-all interview with Oprah Winfrey that she didn't feel "comfortable" speaking about her sibling - who has criticised her several times and even written a tell-all book – as she doesn't particularly know her.

In a clip shared on 'CBS This Morning', Meghan said: "I think it would be very hard to tell all when you don't know me.

"This is a very different situation than my dad, right. When you talk about betrayal, betrayal comes from someone that you have a relationship with. I don't feel comfortable talking about people that I really don't know."

Meghan, 39, and Samantha, 56, share the same father, Thomas Markle, but in her interview the former 'Suits' star was adamant that she grew up "as an only child" and "wished" that she had siblings around her.

Meghan - who also has a paternal half-brother Thomas Markle, Jr. - is grateful that she is expecting a baby girl so her 22-month-old son Archie has someone to build a relationship with.

She said: "That's why I'm so excited to be pregnant, so Archie has someone. The last time I saw (Samantha) must have been at least 18, 19 years ago."

Meghan claimed Samantha changed her name back to Markle when it emerged she was in a relationship with British royal Prince Harry.

The former actress remarked: "I think that says enough."

Meanwhile, Meghan revealed that she considered taking her own life amid public scrutiny of her joining the British Royal Family and opened up to Harry – who lost his mother, Princess Diana, in a car crash in 1997 – about her thoughts.

She explained: "I was really ashamed to say it at the time, and ashamed to have to admit it to Harry especially because I know how much loss he’s suffered, but I knew that if I didn’t say it, I would do it. I just didn’t want to be alive anymore, and that was a very clear and real and frightening constant thought."