Kate, Princess of Wales, apologizes for missing the Irish Guards' final rehearsal before the King's parade

LONDON (AP) — Kate, Princess of Waleswished the Irish Guards good luck for their final rehearsal on Saturday before the match Color Parade parade in honor of the king's birthday.

Kate, who is recovering from cancer, apologized for not attending in her capacity as honorary colonel of the guards.

“Being your Colonel remains a great honor and I am truly sorry that I will not be able to receive the salute at this year's Colonel's Review,” she wrote in the letter shared by the Irish Guards on social media platform . “Please pass my apologies to the entire regiment, but I hope to be able to represent you again very soon.

This review is a dress rehearsal for the annual military parade held each June to mark the official birthday of the monarch. King Charles III will oversee the ceremony on June 15.

It's still unclear whether Kate will attend the ceremony next week. She was treated for an unspecified type of cancer she announced in March after speculation proliferated on social media about her well-being, as she had not been seen in public for several months. She revealed few details about her illness or treatment.

The king returned to his public duties while continuing to undergo his own cancer treatment. He attended the commemorations this week for the 80th anniversary of the Landing, the invasion of Nazi-occupied Europe June 6, 1944.

Trooping the Color is a 460-year-old tradition in which troops in full uniform parade before the king with their ceremonial flag, also known as “the color.”

Charles will likely travel to the event in a horse-drawn carriage with Queen Camilla and is expected to attend the ceremony seated on a dais, rather than on horseback as he did last year.

Irish guards said they were touched by Kate's letter and wished her well.