Watch: Prince Harry opens up about Princess Diana's death in Oprah Winfrey interview
Prince Harry and Meghan Markle have opened up to Oprah Winfrey about leaving life as senior royals in an interview which has been billed as having nothing "off-limits".
The interview has already been recorded, but the timing of the date it will air has caused some "unease", because Harry's grandfather Prince Philip is being treated in hospital.
Philip, 99, went into hospital two weeks ago and was transferred on Monday 1 March to a cardiac specialist facility, St Bartholomew's, where he is being observed for a pre-existing condition.
He's expected to stay in hospital until at least the end of the week, and if he is there over the weekend, the Winfrey sit-down interview with his grandson and granddaughter-in-law will air while he is in his hospital bed.
In a trailer for the interview, airing in the US on CBS on 7 March, Winfrey says "Just to make it clear to everybody, there is no subject that is off-limits", as Meghan nods.
Joe Little, managing editor of Majesty magazine, told The Telegraph there is "unease" about the timing of the interview with the Duke of Edinburgh now in a second hospital.
He said: "This interview has been hyped significantly by CBS and the ball is very much in their court. The transmission date is likely to be set in stone and I can’t imagine it being pulled."
The paper also reported that palace aides are more concerned about Philip, who turns 100 in June, than the interview.
Richard Fitzwilliams, royal commentator, suggested the Duke and Duchess of Sussex should call on Winfrey for some neighbourly assistance in the interview's timing.
He told the Daily Mail: "In the circumstances it would surely be appropriate to postpone the interview which Harry and Meghan are giving to Oprah, which is due to be aired on Sunday, as it involves an examination of the problems they faced when working royals.
"Oprah is their friend and neighbour and would undoubtedly comply if asked and the gesture would I am sure be appreciated by the royal family."
Watch: What Prince Harry told James Corden
Royal editor for the Evening Standard, Robert Jobson, told the MailOnline: "For US broadcast network CBS this interview is a coup, all about securing big viewing figures and big advert sales around the airing of their exclusive interview.
"So even if they wanted to, Harry and Meghan probably couldn't dictate terms to Oprah Winfrey and the network now."
Trailers for the programme were released globally on Monday, but none of 39-year-old Meghan's answers to Winfrey's questions were included.
Instead the network used a clip of Harry, 36, talking about his mother, the late Princess Diana, saying: "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.
“Because it has been unbelievably tough for the two of us, but at least we had each other.”
The interview was extended from 90 minutes to two hours, with reports the show was re-edited after being filmed in mid-February.
The couple confirmed with Buckingham Palace that they would not be returning to their roles as senior royals on 19 February.
Meghan and Harry's interview with Winfrey also comes after Harry opened up to friend James Corden, now host of The Late Late Show in the US, about why he wanted to move his family to California.
In a feature with the Gavin and Stacey star, Harry discussed the "toxic" press in the UK, and said it was "destroying my mental health".
He added: "I will never walk away, I will always be contributing. My life is public service."
Yahoo UK has contacted CBS for comment.
The Oprah Winfrey interview airs in the US on 7 March, with a UK showing to be confirmed.