A journalist has revealed the moment King Charles received a phone call informing him of the Queen's rapidly deteriorating health just hours before she died.

NBC's Today presenter Jenna Bush Hager said she was dining with King Charles in Scotland on the last night he would be the Prince of Wales.

She was there to interview his wife Camilla, but when her flight was delayed she met with King Charles instead.

Speaking on Today, Jenna revealed there was no inkling the Queen's health was deteriorating, with the royal telling her Camilla was "so sad" she couldn't make it due to the delayed flight.

Jenna was due to meet with Camilla the next day upon her return but revealed the interview was cancelled after King Charles received a crucial phone call about the Queen's health.

"The next morning [September 8], we were setting up the interview," she told the program.

"We were at their house, it's called the Dumfries House – they actually bought it, redid it and then gave it to the people of Scotland.

"The interview was supposed to start around 2 or 2.30. I was supposed to meet with the now-queen consort around 1.30. At 12.30, we heard sort of running up and down the halls."

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Jenna then revealed a team for the royals then rushed in and said, "Can you please be quiet. There's a call".

"We were right by then-Prince Charles', now King Charles III's, office. They said, 'He's on a call can you please be quiet'. Then, all of a sudden, we heard a helicopter."

The journalist was then told that her interview with Camilla would have to be postponed.

"They said, 'The Queen is ill, and they have gone and rushed off to be with her'," Jenna remembered.

She said the phone call must have come as a surprise, given the "wonderful" evening she had with King Charles just the night before, adding it was "filled with conversation that felt joyful".

The Queen died on September 8 as relatives rushed to be by her side.

Prince Harry did not get to see his grandmother one more time before her death, with him leaving to make the journey to Balmoral much later than his brother Prince William and other relatives.

According to The Telegraph, “Harry hadn’t even been called” while William was boarding his private jet with Prince Andrew, Prince Edward and Sophie, Countess of Wessex.

The publication reports that the royals didn’t expect the Queen to deteriorate so quickly, and William was summoned by King Charles as a Counsellor of State.

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