How Kate Middleton’s Trooping the Colour appearance took a ‘toll’ amid cancer battle

Kate Middleton fans shouldn’t expect another outing from the Princess of Wales anytime soon following her Trooping the Colour appearance.

Middleton is in need of a “long and well-deserved rest,” royal expert Katie Nicholl told “Entertainment Tonight” Monday.

“I think a day like Saturday where she knows the eyes of the world are on her, there is a huge amount of scrutiny that will take its toll,” she explained. “I don’t think we can expect to see her in public for a little while. That’s going to take some recovery.”

Nicholl compared the royal to a “gliding” swan who was “paddling quite frantically … beneath the water.”

She said that Middleton, 42, attending Saturday’s event amid her cancer battle must have taken “a huge amount of preparation and time and effort and energy.”

The royal reporter added, “She was on her feet for a long period of time. There was a moment where she was watching the parade … and was offered a seat, which she gratefully accepted. That’s just a bit of an acknowledgement that she is not as strong, not as fit, as she was before she went into this treatment.”

Nicholl went on to call the outing the princess’s “decision alone,” as she recently “turned a corner” in her treatment.

Middleton shared her diagnosis in March, two months after announcing a step back from public duties following an abdominal surgery.

Before revealing her health struggles, her absence had spawned conspiracy theories galore online.

Not only did social media users gossip about Prince William allegedly having an affair with Lady Rose Hansbury, which her lawyers denied, but they also spread speculation that Middleton had used a body double for a farmer’s market outing.

Andy Cohen, Blake Lively and more A-listers later apologized for adding to the rumor mill after Middleton’s cancer diagnosis came to light.

The princess addressed her secrecy at the time, saying she and William, 41, wanted to “explain everything” to their three children, Prince George, 10, Princess Charlotte, 9, and Prince Louis, 6, in an “appropriate manner.”

The little ones were present at Trooping the Colour over the weekend, matching in navy outfits.

The couple’s youngest child, as usual, stole the show by dancing on the Buckingham Palace balcony while his sister scolded him.

Middleton wore a white Jenny Packham dress previously worn to a pre-coronation event last year — and upcycled it with a striped bow.