Prince George turned 9 years old on July 22.

Prince William and Kate Middleton shared the traditional birthday portrait that day.

The Queen's official Twitter account shared a video of a military brass band wearing the iconic red uniforms and tall black hats covered in fur playing "Happy Birthday" in George's honor outside his London palace.

The video was captioned, "Thank you @IrishGuardsBand for playing Happy Birthday in honor of Prince George today! The Duke of Cambridge is the colonel of the @irish_guards." The caption was added.

The Irish Guards Band is, according to their Twitter account, "the regimental band of the Irish Guards (Home Department), part of the Royal Army Band."

The Irish Guard as a whole is "an Irish regiment that has proven its loyalty and mettle in many grueling operations," according to the British Army website. Its soldiers have the privilege of guarding the Royal Family. They have been recruited from the island of Ireland, Britain and beyond.

According to a report in the Express, George's father, Prince William, has been a colonel in the Irish Guard since 2011 and wore the corresponding uniform for his royal wedding to Kate Middleton.

As for Prince George's personality as a pre-teen, a source previously told Us Weekly, "George is a hard worker. Like most kids his age, he needs a push at times, but he is very smart and at the top of his class. He is very protective of his younger siblings and goes out of his way to help his mother with chores.