Kate Middleton is skipping a major event for Prince William for a reason every parent would understand

• Kate Middleton won't attend Prince William's Earthshot Prize in Singapore. 
• William confirmed that she's currently helping their son Prince George with his school exams.
• It marks the first time the royal has missed the annual awards ceremony.

Prince William is in Singapore for the Earthshot Prize, an annual environmental awards ceremony he created in 2020. 

But unlike previous years, Kate Middleton won't attend the ceremony, which is due to take place on Tuesday. The princess is staying in the UK to help the couple's son, 10-year-old Prince George, study for school exams, People's Janine Henni and Simon Perry reported ahead of the trip in September.

William confirmed the reason for Kate's absence during a speech on Monday, according to a separate People report by Perry.

"Catherine is very sorry she can't be here," William said, according to Perry. "She is helping George through his first set of major exams."

George is the eldest of the couple's three children and second in line to the throne after William. The couple also share a daughter, Princess Charlotte (age 8), and another son, Prince Louis (age 5).

It's worth noting that it isn't unusual for Kate and William to attend engagements separately. While Kate attended the previous two Earthshot awards ceremonies, held in London in 2021 and Boston in 2022, she did not attend the Earthsot Summit in New York City in September, where William announced the 2023 finalists.

She attended several UK-based solo engagements during the same time period as William's trip, including a visit to East London charity Streets of Growth which supports young people at risk of exploitation, violence, crime, and isolation.

Although it has not been confirmed, the princess' decision to stay at home in September may have also been influenced by the couple's children, People's royals editor Stephanie Petit reported at the time. William and Kate have been photographed driving the children to school on several occasions, and they like to ensure that at least one of them is home most evenings, according to Petit. 

George, Charlotte, and Louis have attended a small number of royal engagements with their parents in recent years, including the monarch's annual birthday parade, Trooping the Colour, and the late Queen Elizabeth's Platinum Jubilee celebrations in London in 2022.

 Kensington Palace did not respond to a request for comment.