Kate Middleton
Kate Middleton is celebrating her 36th birthday on Tuesday. Pictured: Middleton attends Christmas Day Church service at Church of St Mary Magdalene on Dec. 25, 2017 in King's Lynn, England. Getty Images/Chris Jackson

Kate Middleton is turning another year older and wiser on Tuesday.

The Duchess of Cambridge will be celebrating her 36th birthday on Jan. 9. The pregnant mom has been busy with her royal engagements. However, she will have a day off on her special day and will be spending it with her family.

"She will be spending the day privately," the Deputy Communications Secretary told Hello! Middleton is expected to celebrate with Prince William and their children Prince George and Princess Charlotte.

Last year, the duchess also celebrated her birthday privately. Middleton and Prince William had a low-key gathering at their country retreat at Anmer Hall in Norfolk, Mirror reported.

The Duchess of Cambridge celebrated her special day with her parents. A day prior to her birthday, they joined the royal family at Church with Sophie Carter.

Middleton seems to have the same schedule. She was also spotted attending a church service on Sunday just days before her birthday. She was seen walking her way to the church with Prince William and Prince Charles.

Her sister, Pippa Middleton, was present with her husband, James Matthews. Queen Elizabeth was also in attendance at the same church service, but the monarch opted to drive than walk with the rest of the royals.

For the said sighting, Middleton recycled another outfit. The Duchess of Cambridge opted to wear a tweed coat with gold buttons. She paired it with fur trim hat and matching gloves.

Middleton was seen in her military-style jacket during the Christmas Day celebration in 2014. She was also seen in the same hat and gloves multiple times on different occasions.

In related news, Prince William and Middleton are expecting their third royal baby in April. The family of four will become a family of five by then. In addition, Prince Harry's succession to the throne will change. Markle's fiancé will be sixth in line when the Duke and Duchess of Cambridge's youngest baby arrives.

Prince William and Middleton's third baby announcement was not included in the royal family's highlight in 2017. A number of fans reacted as to how the palace could have missed it.

"How about Kate's new pregnancy? Not a highlight?" one user asked.

"How could the Kensington Palace account make four of these year end retrospectives and not once include the fact that the Duke and Duchess of Cambridge are expecting in April? What a strange oversight!" Jane Redmond wrote.