Kate Middleton is known for her soft demeanor and polite personality. However, the royal recently made headlines after she refused to sign autographs during her latest appearance at the Chelsea Flower Show.

The Princess of Wales, on Monday, graced a school event wither presence. She visited the inaugural Children's Picnic, where she joined pupils from St. Mary's Church of England Primary School in Islington and Glenbrook Primary School in Brixton.

Kate surprised the children, who demanded for an autograph from the princess after revealing an unspoken royal rule.

"I can't write my name," the princess politely revealed. "But I can draw," she added, according to People.

"My name's Catherine. I'm not allowed to write my signature, it's just one of those rules," she told the children.

For the uninitiated, this is actually a rule for the British Royal Family members, prohibiting them from signing autographs.

While Kate followed that rule, she also treated the children with a special souvenir and drew a flower for a 7-year-old girl named Ruby.

The princess also drew a tree for another young girl and a pond with flowers for another child.

Prince and Princess of Wales’ official Instagram account also shared a picture of Kate Middleton during her outing.

"Picnic season is upon us, and so is @the_rhs #ChelseaFlowerShow!" the caption read. "What a lovely lunchtime spent with the next generation of nature-lovers, exploring the gardens and enjoying the first ever Children’s Picnic here at Chelsea."