Trooping the Colour details: All eyes on potential Kate Middleton appearance

Trooping the Colour, the annual military parade marking the reigning British monarch's official birthday, is one of the biggest and most highly anticipated events of the year for Britain's royal family.

This year's parade, to be held on Saturday, June 15, comes with more questions than usual.

Since January, both King Charles III and his daughter-in-law Kate, the Princess of Wales, have been diagnosed with cancer and have had to take time away from public duties.

Charles has since returned to a modified schedule of public duties while Kate has not been seen publicly since March, when she revealed her cancer diagnosis in a video message.

Here are your questions answered about who will attend this year's Trooping the Colour and what to expect.

1. Will the king attend this year's Trooping the Colour?

Yes, Charles will attend this year's Trooping the Colour, according to Buckingham Palace.

The king will slightly modify his role in the annual event by riding in a horse-drawn carriage alongside his wife Queen Camilla instead of on horseback, according to the palace.

This year's parade marks the second for Charles as king. His coronation was held on May 6, 2023.

Charles' cancer diagnosis was announced in February. The palace has not specified the type of cancer he has, the stage of cancer or the type of treatment.

2. Will Kate join the royal family at Trooping the Colour?

Kensington Palace has not yet said whether Kate will attend this year's Trooping the Colour.

In past years, Kate has taken part in the parade and watched the military flyover from the balcony of Buckingham Palace alongside her husband Prince William and their three children.

Kate's last in-person public appearance was last December, when she joined members of the royal family at a Christmas Day church service in Sandringham.

When Kate announced her cancer diagnosis in March, which she said came following "major abdominal surgery" in January, the palace said she had begun a course of preventative chemotherapy. No further details have been shared about her treatment or what type of cancer Kate was diagnosed with.

The palace said at the time that Kate would return to official duties when she's cleared by her medical team to do so.

3. Why did Kate issue an apology about Trooping the Colour?

After Kensington Palace confirmed that Kate would miss this year's Colonel's Review, a final rehearsal held one week before Trooping the Colour, the princess issued a written apology to the Irish Guards.

Kate holds the title of honorary Colonel of the Irish Guards.

"I wanted to write and let you know how proud I am of the entire regiment ahead of the Colonel's Review and Trooping of the Colour," she wrote in the letter, posted on X by the regiment. "I appreciate everyone trooping this year has been practicing for months and dedicating many hours to ensuring their uniforms and drill are immaculate."

Kate continued, "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."

4. Will the public see William and Kate's kids at Trooping the Colour?

The palace has not yet said whether William and Kate's children, Princes George and Louis and Princess Charlotte, will make their traditional appearance at Trooping the Colour.

Last year, the Wales children joined Kate and Camilla in a carriage along the parade route, and then joined other members of the royal family on the balcony of Buckingham Palace to watch a flyover.

5. Will Prince Harry and Meghan join the royals this year?

No, Prince Harry and Meghan, the Duchess of Sussex, are not expected to attend the king's birthday parade.

Harry, Charles' younger son, and Meghan live in California with their two young children and are no longer senior working royals.

Harry and Meghan's last public appearance with the royal family at Trooping the Colour was in 2019, shortly after Meghan gave birth to the couple's eldest child Archie.

The Sussexes also attended the late Queen Elizabeth II's Trooping the Colour in 2022, on the occasion of her Platinum Jubilee. Harry and Meghan did not join other royal family members on the balcony of Buckingham Palace though because they are no longer working royals.

6. What happens during Trooping the Colour?

The parade, which will begin around 5 a.m. ET on Saturday, travels from Buckingham Palace, down the Mall and to the Horse Guards Parade before returning to Buckingham Palace.

Over 1,400 soldiers and military officers take part in the parade, which also includes 200 horses and over 400 musicians from 10 military bands, according to the U.K.'s Household Division.

On arrival at Horse Guards Parade, the royal party goes to a viewing position on a balcony overlooking the parade ground while the king, having inspected the troops, watches from a special platform, or dais, on the parade ground as the soldiers parade past.

After the parade, the royal party returns along the Mall in their carriages.

The king will then take a final salute before joining the rest of the royal family on the balcony at Buckingham Palace for the Royal Air Force flypast to mark his birthday.