King Charles is shouting out his sister Princess Anne in a royal way on her birthday.

Princess Anne turned 74 on Aug. 15, and the King’s team sent well-wishes on social media to celebrate the occasion.

“Wishing the Princess Royal a very Happy Birthday today!” courtiers wrote on X, referring to the King’s sister by her royal title, along with a birthday cake emoji and three photos.

The images showed Princess Anne at the Not Forgotten Association Annual Garden Party at Buckingham Palace in London in May as well as Princess Anne and King Charles in military uniform at a rehearsal for Trooping the Colour in June 2023.

A third snap was a sweet throwback photo of the brother and sister as children, smiling as they sat together on a blanket in the grass.

Wishing The Princess Royal a very Happy Birthday today! 🎂 pic.twitter.com/5S85cViZ7k

— The Royal Family (@RoyalFamily) August 15, 2024

King Charles, 75, and Princess Anne were born less than two years apart and are known to be close. Ahead of Princess Anne’s participation in the procession through London following the coronation of the King and Queen Camilla, Anne’s daughter, Zara Tindall, said that the thoughtful honor reflected the tight bond her mother and uncle share.

“It’s a busy time for them all, and her and her brother are very close, so it’s a nice thing to do,” Zara told PEOPLE before the crowning ceremony.

King Charles’ team referred to Princess Anne as the Princess Royal in the latest birthday well-wish, respectfully citing the title she received from their late mother, Queen Elizabeth, in June 1987 at age 36.

The Princess Royal is the traditional title for the monarch’s eldest daughter and is held for life. Princess Anne is the only daughter of Queen Elizabeth and the late Prince Philip and the seventh Princess Royal in the history of the British monarchy, according to the royal family’s website.

Princess Anne began undertaking public engagements at age 18 and hasn’t stopped since. She is connected to over 300 charities, organizations and military regiments in the U.K. and around the world and is regularly cited as the “hardest-working royal” by the count of official engagements recorded in the Court Circular, the royal family’s official record of previous engagements.

Many of the royal’s patronages and other supported causes also shared birthday wishes on Aug. 15, including the Royal College of Anaesthetists, the Woolf Institute and the British Horseracing Authority.