How to Send Kate Middleton a Card amid Her Cancer Treatment (and You Might Get a Royal Reply)

Kate Middleton could be your royal pen pal.

As the Princess of Wales, 42, receives cancer treatment, fans may want to send the royal a letter or card filled with well wishes.

On April 6, X user AllexmarieHoll1 shared a short note they said they received after sending a card to Princess Kate following the palace's announcement that she had undergone abdominal surgery in January. The fan's royal reply on Kensington Palace stationary said, "Thank you for your kind well wishes to Her Royal Highness. The Princess of Wales. Your thoughtful gesture is very much appreciated."

Many royal fans have been sending members of the family mail for special occasions such as birthdays, holidays, wedding anniversaries and major events like last year's coronation. (Prince William and Princess Kate's team even reportedly responded to a young girl who invited Prince George to her birthday party!)

AllexmarieHoll1 shared they sent their latest correspondence to Princess Kate at:
"HRH The Princess of Wales
Clarence House
London SW1A 1BA United Kingdom."

Although Princess Kate, Prince William and their three children live primarily in Windsor, their London base is Kensington Palace. According to other royal fan sites, mail can also be sent to them there by using the address:
"Kensington Palace
London W8 4PU."

According to the royal family’s website, King Charles is also interested in letters from the public.

"The King is shown almost all of his correspondence on a daily basis by one of his Private Secretaries, and he takes a keen interest in the letters he receives," Royal.UK says of the monarch.

The website says people can write to King Charles via:
"His Majesty The King
Buckingham Palace
London SW1A 1AA, United Kingdom."

King Charles, 75, recently appeared in a video reading some of the thousands of cards and letters that he received after announcing in February that he is undergoing cancer treatment. Among them was a humorous oversized card depicting a dog wearing a veterinary cone with the caption: "King Charles, at least you don’t have to wear a cone!" Another struck a more emotional tone with the message, "The main thing is family."

Etiquette expert Debrett’s gives even more guidance around how to address several members of the royal family in writing. 

"Unless you are personally known to the Sovereign, any letter to The King or Queen should be addressed to ‘The Private Secretary to His Majesty The King.' There is no need to address the private secretary by name, but if there is subsequent correspondence this should be addressed to the actual writer of the reply," according to Debrett's.

The site adds that letters to King Charles and Queen Camilla should begin with "‘Sir,' 'Madam' or ‘May it please Your Majesty’ " opening with the line "With my humble duty" and ending with the language "‘I have the honor to remain, Sir/Madam, Your Majesty’s most humble and obedient servant,’ " with the option to swap "remain" for "be."

Envelopes should be addressed to "His Majesty The King" or "Her Majesty The Queen," and the styling for cards to Princess Kate and Prince William are similar. According to the peerage authority, envelopes containing mail for Prince William should be addressed as "The Prince of Wales, KG, KT," shorthand for his status as a Royal Knight Companion of the Most Noble Order of the Garter and Knight of the Most Ancient and Most Noble Order of the Thistle. The honors are the highest orders of chivalry in Britain and Scotland, respectively.

Meanwhile, the envelopes of cards for Princess Kate should be addressed to "The Princess of Wales, GCVO," signifying her position as a Dame Grand Cross of the Royal Victorian Order. The Royal Victorian Order was established by Queen Victoria in 1896 to allow her to recognize people who helped her or represented her. The ruling monarch personally selects recipients of the honor, and Princess Kate received the rank from Queen Elizabeth in 2019.

Fans from the United States should add an international stamp, available to purchase at post offices, for the mail to make its way across the pond. Then, keep an eye on your mailbox for a reply.

Buckingham Palace opened up about the increase in mail following the death of Queen Elizabeth in Sept. 2022. Prior to the record-setting monarch's death, the palace received up to 1,000 letters each week from members of the public, but their mailboxes were flooded with 50,000 letters and messages of condolence in the weeks following the Queen's death.

The palace said at the time that all letters are carefully read and responses would be sent as the small correspondence team processes the influx of mail.

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During a solo visit to the Shrewsbury Farmers’ Market on March 27, Queen Camilla was showered with messages for Princess Kate after the Princess of Wales announced her cancer diagnosis. The Queen, 76, warmly promised to deliver posters that two young girls made for her that read, "Send our love to Kate"

"Her Majesty said: 'I know that Catherine is thrilled by all the kind wishes and support,' " royal editor Rebecca English of the Daily Mail wrote on X.