The Prince and Princess of Wales aren’t the only royals who received new appointments

Kate Middleton and Prince William are taking on new royal appointments.

On April 23, which happens to be the sixth birthday of the Prince and Princess of Wales’ son Prince Louis, King Charles announced several new appointments, including for members of the royal family.

The King, 75, appointed his daughter-in-law Princess Kate, 42, as the Royal Companion of the Order of the Companions of Honour. In a history-making twist, she is the first Royal Companion named to this order.

The Order of the Companions of Honour was founded by King George V in 1917 to recognize outstanding achievements in the arts, sciences, medicine and public service. Members are limited to 65 at a time (although people from outside Commonwealth countries can be counted as additional honorary members) and currently include David Attenborough, Elton John, Anna Wintour, Judi Dench and Maggie Smith.

Related: Kate Middleton Found ‘Comfort’ in Public Reaction to King Charles’ Cancer Diagnosis

Princess Kate’s new appointment from King Charles comes as they are both undergoing treatment for cancer.

“He has always had a very good bond with her. I don’t think it is presumptuous to say that she is like the daughter he never had,” royal biographer Sally Bedell Smith recently told PEOPLE. “He shares with William an impulse to protect her. They are in this together, Kate and the King.”

Buckingham Palace said that King Charles was “so proud of Catherine for her courage in speaking as she did” to announce her cancer news on March 22.

Apart from being King and future queen, they are also “two patients going through a common health experience,” added a royal source, noting they “are bound to have a close connection…I imagine there was some comfort [for Kate] in seeing…that it was possible to balance some private information without there being an imperative to share all.”

Prince William, 41, was appointed by his father to be Great Master of the Most Honourable Order of the Bath. The role had been vacant since 2022 after King Charles, who held the role from 1974 to 2022, acceded to the throne.

The Most Honourable Order of the Bath was established by King George I in 1725 but is believed to originally date back as far as the eighth century. It is awarded to members of the military or civil service for exemplary service.

Queen Camilla also received a new appointment from her husband as the Grand Master and First or Principal Dame Grand Cross of the Most Excellent Order of the British Empire.

The Order of the British Empire was established by King George V in 1917 to honor a broader cross-section of society, both military and civilian. It comprises five classes, the two most senior of which makes the recipient a knight or dame.

The title of Grand Master has twice before been held by the monarch’s spouse with Prince Philip (1953 to 2021) and Queen Mary (1936 to 1953). King Edward VIII, who was known as the Duke of Windsor following his abdication, held the role from 1917 to 1936 as the Prince of Wales.

Related: Prince William Promises to ‘Look After’ Kate Middleton amid Cancer Treatment While Receiving Cards for Her and King Charles

Keeping with the tradition of appointing new Companions to the Order of the Garter on April 23, the feast day of England’s patron saint St. George, King Charles named four members. This included a member of the royal family: the Duchess of Gloucester. The Duchess, 77, is the wife of the late Queen Elizabeth’s cousin the Duke of Gloucester and a full-time working member of the royal family.

The other three new Order of the Garter members include Air Chief Marshal Lord Peach, the Right Honourable Lord Kakkar and Lord Lloyd-Webber.

The Order of the Garter is the oldest and most senior Order of Chivalry in the U.K., established by King Edward III nearly 700 years ago. Each year, it is celebrated with a procession and service on the grounds of Windsor Castle, complete with members wearing the Order of the Garter velvet robes and hats adorned with an ostrich feather.

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The four new members bring the total number of Companions to 21, out of a maximum of 24. Other royal family members in the Order of the Garter include Queen Camilla and Prince William.