Prince William just turned another year older.

On Thursday, the Duke of Cambridge celebrated his 36th birthday. However, he is away from his wife, Kate Middleton, and their three children, Prince George, Princess Charlotte and Prince Louis, because he has a royal engagement.

"Today the @DNRCOfficial, a world-class rehab facility for Armed Forces personnel who have suffered major trauma or injury, was handed over to the nation," Kensington Palace announced. "At the ceremony, The Duke of Cambridge read 'One for the Team' by Debbie Lawson, winner of the 'Poem to Remember' competition."

To celebrate Prince William's birthday, Clarence House shared a throwback photo of the duke with the Prince of Wales on Twitter. In the black and white snap, Prince Charles was holding Prince William on his lap. Another snap featured the royal father-and-son in a recent engagement they attended together. "Happy 36th Birthday to The Duke of Cambridge! #HappyBirthdayHRH," the caption read.

Just recently, Prince William and Middleton announced the date of Prince Louis' christening. The couple opted to have the ceremony on the same chapel where Meghan Markle was baptized.

"The Duke and Duchess of Cambridge are pleased to announce that the christening of Prince Louis will take place on Monday 9th July at The Chapel Royal, St James’s Palace, London," the palace said in a statement.

Prince William and Middleton are keen to make the occasion a private affair, but they will make a compromise. The couple is expected to share photos of the event because they understand that the public wants to have updates about their newborn.

"Judging by the previous christenings, and the importance of the day for the family, Louis’ christening will be a private affair, perhaps no surprise there," James Brookes told Express. "The Cambridges are well aware of the media spotlight on and interest in their family - we saw that with the recent photos of Prince George and Princess Charlotte playing at the polo match."

"We'll no doubt have the official christening photos, as we did with Prince George and Princess Charlotte," he added. "These photos, and the images of the family arriving will be seen as a compromise by the Cambridges. They give the photographers something to work with and then they expect a bit of privacy for the rest of the day."