Kate Middleton, Prince George and Princess Charlotte
Kate Middleton hunts spider with Prince George and Princess Charlotte. Pictured: Prince George, Middleton and Princess Charlotte look out from the balcony of Buckingham Palace during the Trooping the Colour parade on June 17, 2017 in London. Getty Images/Chris Jackson

Kate Middleton knows how to have fun with her kids, but some of their shared activities may seem strange to others.

On Tuesday, the Duchess of Cambridge has officially returned to her royal duties. She wore casual jeans, boots and a baggy coat at a large outdoor learning center in Paddington, London, where she was welcomed by kids.

During the outing, Middleton revealed a creepy activity that she does with her kids, 5-year old Prince George and 3-year-old Princess Charlotte. Zoe Stroud, interim head of Sayers Croft Forest School, told People that Middleton "was lovely, although she said the only mini beasts she managed to find on the hunt was a slug! But she did see a frog under a log."

She also revealed that Middleton has a seemingly weird activity that she does with her kids. "[Kate] really gets what we are doing here and said she often takes her children on spider hunts in their garden, which they love," Stroud. "They can spend hours out there."

An onlooker also praised the Duchess of Cambridge as a mom. Based on the way she treated the children, Middleton is apparently a "fantastic mum" because "she was calm with the children."

In the same outing, one girl also asked Middleton why the photographers are taking pictures of her. Prince William's wife gave a sweet response to the student. "They're picturing you cause you're special!" Middleton said. The duchess then grabbed the child's hand, and they walked towards a picnic table.

In related news, Middleton broke royal protocol during her first royal engagement after her six-month maternity leave. First, she was seen attempting to close the car door. She pushed it after she stepped out.

Upon arrival, she hugged the schoolchildren, who welcomed her after they initiated the embrace. She was also seen in pants. Usually, royals don’t wear pants. In fact, Meghan Markle received intense backlash after wearing one for her evening debut.

In related news, Prince William and Middleton will be reuniting next week for their first engagement together since she returned to her royal duties. The Duke and Duchess of Cambridge will attend the first Global Mental Health Summit at County Hall in London on Tuesday. They will also listen to the "Children, Young People and the Next Generation." workstream and two case study presentations from Slovenia and the U.S.