The Princess of Wales joined the British royals at King Charles’ birthday parade, marking her first public outing with the royals since Christmas.

Kate Middleton was a welcomed sight at Trooping the Colour, making her first royal outing since Christmas amid her cancer diagnosis.

The Princess of Wales, 42, joined the royal family at King Charles’ birthday parade on June 15. After arriving at Buckingham Palace by car with her family, she took part in the procession by riding in a horse-drawn carriage through London with her three children: Prince George, 10, Princess Charlotte, 9, and Prince Louis, 6.

The royal mom, sporting a white dress by Jenny Packham adorned with the Irish Guards Regimental Brooch and paired with a hat by Philip Treacy, and kids traveled in the Glass Coach, shielding them from the rainy weather. The Glass Coach, built in 1881 and purchased for King George V’s coronation in 1911, has brought many royal brides to their weddings, including Princess Anne in 1973, Princess Diana in 1981, and Sarah Ferguson in 1986.

Princess Kate has attended Trooping the Colour every year since marrying Prince William in 2011, except for 2020 and 2021 when the event was scaled down due to the COVID-19 pandemic.

Princess Kate’s attendance at King Charles’ annual birthday parade was confirmed the day prior as she released a new photo and personal letter featuring an update on her health. After undergoing abdominal surgery in January, the royal announced in an emotional video released on March 22 that post-operative tests led to a cancer diagnosis and that she was undergoing chemotherapy.

“I’m looking forward to attending the King’s Birthday Parade this weekend with my family and hope to join a few public engagements over the summer, but equally knowing I am not out of the woods yet,” she said in the June 14 message.

Her appearance at Trooping the Colour marked the first time she stepped out for a royal event since December when she joined the family at their annual Christmas church visit. Kate made a number of outings that month, from hosting her third annual Christmas carol concert to sporting a tiara for the Diplomatic Reception at Buckingham Palace.

While Princess Kate has maintained a low public profile in the months since her cancer announcement as she focuses on recovery, she was recently spotted out with her family as well as running errands solo, sources told PEOPLE. The Princess of Wales said in her June 14 message that she is “starting to do a little work from home” and expressed a “hope to join a few public engagements over the summer,” but no date has been set for her to fully return to her royal duties. Any outings in the near future will be based on when she feels able and under the guidance of her medical team.

Princess Kate did not attend the Colonel’s Review, the final rehearsal for Trooping the Colour that took place one week prior on June 8. She is the honorary Colonel of the Irish Guards, who are leading the charge in this year’s celebration (only one flag can be trooped at a time, so the five regiments of the Foot Guards — Grenadier, Coldstream, Scots, Irish and Welsh — rotate annually). The Princess of Wales would normally have taken the salute at the Colonel’s Review, but the palace announced on May 30 that she would not carry out the moment. Instead, Lieutenant General James Bucknall, a former Commander of the Allied Rapid Reaction Corps who has attended every Trooping the Colour since 2009 when he was appointed Colonel of the Coldstream Guards, took the salute at the practice event.

In a letter shared with the Irish Guards, Kate said, “Being your colonel remains a great honor, and I am very sorry that I’m unable to take the salute at this year’s Colonel’s Review. Please pass my apologies to the whole Regiment, however, I do hope that I am able to represent you all once again very soon. Please send my very best wishes and good luck to all involved.”

The Princess of Wales signed her name as “Colonel Catherine.” Amid his own cancer diagnosis and treatment, King Charles attended Trooping the Colour — with a slight change from previous years. Although the monarch, 75, previously appeared on horseback in the procession, he rode in a horse-drawn carriage alongside Queen Camilla for the procession.

The King recently resumed a fuller schedule of royal duties, including public outings.