The Duke of Sussex has told Oprah Winfrey his biggest fear was "history repeating itself," a reference to the death of his mother, as he explained his decision to leave royal life.
Meanwhile, his wife, the Duchess of Sussex, appeared to suggest that her experiences in Britain had been "almost unsurvivable”.
CBS, the US television network, released two 30-second excerpts from Oprah With Meghan And Harry: A CBS Primetime Special, the blockbuster interview which will be broadcast in full on March 7.
The first opens with Ms Winfrey talking to the Duchess alone, seated on garden furniture on a patio.
Ms Winfrey asks the Duchess: "Were you silent, or were you silenced?”
The chat show host then makes clear to viewers that "no subject is off limits" in the interview. Addressing the Duchess, Ms Winfrey then says: "Almost unsurvivable sounds like there was a breaking point?”
Viewers are not shown the Duchess's answer, but the Duke is shown saying: "My biggest fear was history repeating itself.”
The first clip ends with Ms Winfrey saying: "You've said some pretty shocking things here."
In the second clip the couple are seen seated together holding hands.
The Duke says: "You know, for me, I'm just really relieved and happy to be sitting here talking to you with my wife by my side.
"Because I can't begin to imagine what it must have been like for her going through this process by herself all those years ago.”
During his comments CBS showed a clip of the Princess of Wales holding the Duke as a young boy.
The Duke went on: "It has been unbelievably tough for the two of us but at least we have each other.”
The Duchess added quietly: “Yeah."
It was the only time the Duchess is heard speaking during either clip.
The Duke, dressed in a grey suit and white shirt, and the Duchess, in a long black dress, both looked to have become emotional during the interview.
It came days after the broadcast of the Duke's 17-minute segment on James Corden’s The Late Late Show.
In that appearance the Duke blamed the media for his departure from royal life, saying the British press was “destroying his mental health." The Duke said it had become so "toxic" he decided he had no option but to remove his family from the situation.
A CBS spokeswoman said the interview would be broadcast in a two-hour special.
The network said: "It covers everything from stepping into life as a Royal, marriage, motherhood and philanthropic work, to how she is handling life under intense public pressure.
"Later, the two are joined by Prince Harry as they speak about their move to the United States and their future hopes and dreams for their expanding family."
CBS had initially said the interview would be a 90-minute special, but that has been increased to two hours.
According to people close to Ms Winfrey it is "the best interview she's ever done."
Recently, Ms Winfrey's longtime friend, television personality Gayle King, said: "We want to remind you Harry and Meghan are talking to Oprah.
"It's their first major broadcast since giving up their senior royal duties and I've heard from reliable sources - this is Oprah talking - that it's the best interview she's ever done.
"So I'm curious. I think that's saying something."