Princess Kate refuses to be a 'people pleaser' in new Royal Family strategy

"Kate might be back, but she's doing it sensibly, and on her own terms," Seward said.

"Her priorities have changed and she's listening to her body, instead of being a people pleaser. She's absolutely got to be strict with herself and say: 'No, I can't do this.'"

Seward noted that whilst the Princess appears healthy, maintaining such appearances requires significant effort, telling Hello!: "Maybe we've been lulled into a sense that we'll be seeing her all the time again, because she looks so amazing. But it must be an effort to look like that when you're not 100 per cent full of energy."

The Princess cancelled her planned appearance at Royal Ascot last week just 90 minutes before the traditional carriage procession was due to begin. She had been expected to join Prince William and other senior royals at the Berkshire racecourse on Wednesday.

Seward explained the demands of such events: "Ascot is more exhausting than it looks; it involves an early start, and there's a long process of hair and make-up and getting the right outfit.

"The royals have lunch at Windsor Castle; then there is a bumpy carriage ride while the whole world is looking at you. It was a very hot day, and she probably simply didn't feel up to it."

Despite missing Ascot, the Princess has made several successful appearances recently. She attended the Garter Day procession at Windsor Castle on Monday, wearing a white Self-Portrait ensemble whilst sharing light moments with the Duchess of Edinburgh.

The weekend before, she participated in Trooping the Colour, riding in a carriage and appearing on Buckingham Palace's balcony with her family for the Red Arrows flypast.

"I'm sure she was disappointed and really wanted to be there at William's side," Seward said of the Ascot cancellation.

"She loves racing and so does her mum. But this was a social event for fun and pleasure rather than an official or charity engagement, so I think it was a wise decision, even though it was probably a difficult one, too."

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The Princess has completed over 20 official engagements this year, including a visit to the V&A East storehouse and a trip to the Isle of Mull with Prince William in April.

Looking ahead, the family is expected to attend Wimbledon before spending the summer holidays at Anmer Hall in Norfolk. A family holiday, possibly to the Scilly Isles, is anticipated before their traditional August visit to Balmoral.

Seward emphasised the Princess's long-term approach to recovery: "She is definitely playing the long game and prioritising what is important - her family, her health and staying well."