Prince William is concerned for his brother Harry and his wife Meghan after the couple said they were struggling, a Palace source has told the BBC.
The Duke of Cambridge is said to be “worried” about Prince Harry and hopes he and Meghan “are all right” after the admission in an ITV documentary.
The Palace source added that there was a view the couple were “in a fragile place”.
Kensington Palace had no comment on the ITV film, which aired on Sunday.
The documentary followed the Duke and Duchess of Sussex on their tour of southern Africa earlier this month.
In interviews, the couple both said they were struggling with the intense scrutiny from elements of the British tabloid press.
Meghan, 38, said adjusting to royal life had been “hard”.
“When I first met my now-husband my friends were really happy because I was so happy,” she said.
“But my British friends said to me, ‘I’m sure he’s great but you shouldn’t do it because the British tabloids will destroy your life’.”
‘Not really OK’
Asked by ITV’s Tom Bradby if it was fair to say she was “not really OK”, the duchess said: “Yes.”
Prince Harry, 35, described his mental health and the way he deals with the pressures of his life as a matter of “constant management”.
He said: “I thought I was out of the woods and then suddenly it all came back, and this is something that I have to manage.
“Part of this job is putting on a brave face but, for me and my wife, there is a lot of stuff that hurts, especially when the majority of it is untrue.”
The Palace source played down suggestions that Prince William was “furious” with his brother after the documentary aired on Sunday.
It followed Prince Harry’s admission in the film that he and William have “good days” and “bad days”.
The duke added: “We are brothers. We will always be brothers.
“We are certainly on different paths at the moment but I will always be there for him as I know he will always be there for me.”
The royal brothers previously campaigned together to help open up conversations about mental health.
In 2017, the siblings and Catherine, Duchess of Cambridge, took part in a charity fundraiser for their Heads Together initiative, which they set up to challenge stigma around mental health.
In May this year, the Cambridges and the Sussexes teamed up to launch a text messaging service for those experiencing a mental health crisis.
The couples later announced their charitable foundation would split, but vowed to continue working together on issues like mental health.
Prince Harry’s comments about the pressure of media scrutiny comes as he and his wife pursue legal actions against the press, with Meghan suing the Mail on Sunday over a claim that it unlawfully published one of her private letters.
The duke filed his own proceedings at the High Court against the owners of the Sun, the defunct News of the World, and the Daily Mirror, in relation to alleged phone-hacking dating back more than a decade.