Prince Harry has said he feared "history repeating itself" and the process of leaving royal life has been "unbelievably tough" for him and his wife Meghan.
The Duke and Duchess of Sussex spoke to Oprah Winfrey about life in and out of the Royal Family.
The interview with Winfrey, who lives near the couple's new home in Montecito, California, will be screened in the UK on 8 March, a day after it airs in the US.
In one of two 30-second promo clips released by CBS on social media, Harry says: "I'm just really relieved and happy to be sitting here talking to you with my wife by my side."
As a photo was shown of him as a child with his mother, Princess Diana, he continued: "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, because it's been unbelievably tough for the two of us.
"But at least we have each other."
The Duke and Duchess of Sussex were shown sitting outdoors beside each other, Harry in a grey suit and Meghan – who is pregnant with their second child – in a black dress.
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A second clip contains Harry saying: "My biggest concern was history repeating itself" but the remainder is dominated by Winfrey, with statements such as: "You said some pretty shocking things here," and "almost unsurvivable – sounds like there was a breaking point?" without any indication of what she is referring to.
Meghan's answer is not heard in either of the two clips.
Analysis: Diana comment is 'swipe at the royals and his father'
By Rhiannon Mills, royal correspondent
It's the most anticipated royal interview in recent years so it's hardly surprising the producers of Oprah's 90-minute chat with Harry and Meghan have gone full high drama in the promo.
But as well as the ominous and moody music, they've been clever with their choice of clips too.
We don't hear from Meghan, we only see her face as Oprah teases us with questions and statements: "Were you silent or were you silenced?", "you've said some pretty shocking things here" – all of it just leaving us wondering what on earth the Sussexes have told her?
The one person we do hear from is Harry, comparing their experience to his mother's.
We've heard him talk before about his fear that history was repeating itself; that he didn't want to see Meghan tormented by the tabloids and the paparazzi in the same way as Princess Diana.
It is admirable that he would want to defend his wife and speak so lovingly about his mother. But his comment also comes across as a considerable side swipe at the Royal Family and his father, Prince Charles, as he talks about his mother having to deal with her troubles alone.
In the past I think Harry would have been more circumspect in his choice of words. If we wondered whether the Sussexes were going to be subtle in their answers or hold back I think we have our answer.
As the big build up begins, we have just a week until we find out what those "shocking" revelations are – and who will be blamed for making their lives "unbelievably tough" and "almost unsurvivable".
But the couple stepped away from full-time royal life in March 2020, unhappy about the media scrutiny, intrusion, restrictions of their roles, and racist attitudes shown by some towards the duchess.
Last month, it was confirmed that they would not return to royal duties, meaning Harry will give up his honorary military titles.