Kate Middleton made a surprising return to public life at King Charles’ official birthday celebration, however, an insider has revealed shocking details about what went on her mind.

Speaking with Life & Style, a source revealed that Kate was skeptical about her looks before appearance at Trooping the Colour.

“Kate was nervous making her reappearance,” the insider told the publication. “She worried she would look tired or too thin at the parade, but she looked amazing.”

But, “the supportive response Kate got,” especially from her husband Prince William, “boosted her confidence, and it was apparent,” they added.

“Kate was exhausted afterward,” the insider said. “It was a long day, and it took a lot out of her.” Afterwards, she wrote the post about having good and bad days amid chemotherapy.

They said Kate knows she is not the only one “battling cancer, and she realizes that being truthful about her struggle will help others.”

Hence, she is “learning how to be patient,” the insider said, adding, that Kate is hoping to attend “a few engagements” this summer.

Before concluding, the insider said the Princess of Wales knows she’s “not out of the woods yet.”

“Her display of strength proves she’ll make a worthy queen one day,” the insider shared. “She’s a fighter, for herself, her family and her country.”