Kate Middleton will have to spend part of her birthday without husband Prince William and kids Prince George and Princess Charlotte.

On Wednesday, the Duchess of Cambridge will turn 37 years old. However, the majority of her family members will be away on her special day.

According to Nicholas Beiber, royal correspondent for Daily Star, Middleton’s children are now back to school. Prince George, 5, is said to have returned to St. Thomas’s Battersea on Tuesday. His younger sister, Princess Charlotte, 3, also went back to Willcocks Nursery School in Kensington. The two are expected to attend classes on Wednesday.

Meanwhile, Middleton’s husband, Prince William, will also be away. The Duke of Cambridge is set to visit London’s Air Ambulance since the charity will be celebrating its 30th anniversary. The charity is close to the father of three who previously worked as an air ambulance pilot for the East Anglian Air Ambulance.

Although Prince William, Prince George and Princess Charlotte will be away from home, Middleton won’t be alone because her youngest son, Prince Louis, is with her. Also, the family is expected to reunite later in the day.

Prince George and Princess Charlotte will be home after their classes. Also, Prince William’s engagement will only take a few hours and he will spend the rest of the day with his wife and kids. So, the family still has time to celebrate Middleton’s birthday together.

Last year, the Duchess of Cambridge celebrated her birthday privately. She will likely do the same this year. The members of the royal family usually take a day off from their royal duties on their birthday and celebrate it at home with their loved ones.

Meghan Markle gifted Middleton a leather-bound dream diary in the previous year. Royal fans are looking forward to what the Duchess of Sussex will give her sister-in-law this time especially since they just mended fences.

Middleton and Markle were rumored to be feuding for a year. The two duchesses couldn’t get along well with each other, according to several outlets.

The two royals reportedly ended their rift over the holidays when they celebrated Christmas with Queen Elizabeth II in Sandringham. They even appeared friendly toward each other during the royals’ traditional Christmas Day service.