Royal duty calls!Kate Middletonis celebrating her 37th birthday on Wednesday, but she will be spending at least part of the day away from her husband.That’s becausePrince William, 36, has a solo engagement: He will be visiting staff members of London’s Air Ambulance, which is celebrating its 30th anniversary this year. William is set to meet with the charity at the Royal London Hospital in Whitechapel, where he’ll join staff, patients and their families at a tea party marking the anniversary.It’s not unusual for royals to make public outings on days that coincide with a family event. In November,Prince Williamand Kate (rocking an apron!)visited the homelessness charity Centrepointjust hours before getting glammed up forPrince Charles‘70th birthday bash at Buckingham Palace.Kate Middleton and Prince William.BEN STANSALL/AFP/GettyCan’t get enough of PEOPLE’s Royals coverage?Sign up for our newsletterto get the latest updates onKate Middleton,Meghan Markleand more!With the couple’s two eldest children – 5-year-oldPrince Georgeand 3-year-oldPrincess Charlotte– heading back to school next week following the Christmas break, Kate will likely spend most of the day withPrince Louis, 8 months. The family will likely all be together for a small celebration that evening.Matt Porteous/PA WireThe family was also together over the holiday, when they spent time at their Anmer Hall home. Kate even revealed to fans that George and Charlotte gave them avery early wake-up call on Christmas.Kate Middleton and Prince William.Samir Hussein/WireImageWhen awell-wisher at their annual Christmas church outing asked the pair how early they got up, William replied, “This morning was about 5 a.m.” Kate smiled at the answer as the crowd moaned at the early time.Another royal fan, Jill Lee, told reporters that Kate shared a similar story. “I said to Kate, ‘Were the children up early?’ and she said, ‘Very early, but it was lovely to see their faces,’ ” according toHello!

Royal duty calls!

Kate Middletonis celebrating her 37th birthday on Wednesday, but she will be spending at least part of the day away from her husband.

That’s becausePrince William, 36, has a solo engagement: He will be visiting staff members of London’s Air Ambulance, which is celebrating its 30th anniversary this year. William is set to meet with the charity at the Royal London Hospital in Whitechapel, where he’ll join staff, patients and their families at a tea party marking the anniversary.

It’s not unusual for royals to make public outings on days that coincide with a family event. In November,Prince Williamand Kate (rocking an apron!)visited the homelessness charity Centrepointjust hours before getting glammed up forPrince Charles‘70th birthday bash at Buckingham Palace.

Kate Middleton and Prince William.BEN STANSALL/AFP/Getty

BRITAIN-ROYALS-MEDIA-CHARITY-INTERNET

With the couple’s two eldest children – 5-year-oldPrince Georgeand 3-year-oldPrincess Charlotte– heading back to school next week following the Christmas break, Kate will likely spend most of the day withPrince Louis, 8 months. The family will likely all be together for a small celebration that evening.

Matt Porteous/PA Wire

Prince Louis christening

The family was also together over the holiday, when they spent time at their Anmer Hall home. Kate even revealed to fans that George and Charlotte gave them avery early wake-up call on Christmas.

Kate Middleton and Prince William.Samir Hussein/WireImage

The Duke & Duchess Of Cambridge Visit South Yorkshire

When awell-wisher at their annual Christmas church outing asked the pair how early they got up, William replied, “This morning was about 5 a.m.” Kate smiled at the answer as the crowd moaned at the early time.

Another royal fan, Jill Lee, told reporters that Kate shared a similar story. “I said to Kate, ‘Were the children up early?’ and she said, ‘Very early, but it was lovely to see their faces,’ ” according toHello!

source: people.com