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London is preparing for the annual Trooping the Colour parade, as the world waits to see The Princess of Wales in her first public appearance this year.
Catherine said she is making good progress in her cancer battle, confirming she will attend the King's Birthday Parade in a statement this morning.
Her Royal Highness will be in a carriage procession with her children and is due to make an appearance on the Buckingham Palace balcony, the BBC reports.
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The parade is due to begin at 10.30am (7.30pm AEST).
Catherine has been largely out of the public eye while undergoing chemotherapy for an unnamed cancer announced in March.
She holds the title of Colonel of the Irish Guards and this year it will be those guards who take the lead.
The traditional military spectacle will draw massive crowds to central London, as thousands of soldiers will parade for the public and members of the royal family.
More than 1400 officers and soldiers from the King's personal troops will be on display, alongside hundreds of musicians from the regimental bands.
At the start of the ceremony, the King will be greeted by a 41-gun salute.
King Charles III, in his second Trooping the Colour as monarch, will then inspect the massed troops.
The King will be in a carriage rather than on horseback after his cancer diagnosis.
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Following a performance by the military bands, the regiments will "troop" their colour, as each regiment's flag is processed down the ranks of soldiers.
This year, 75-year-old Charles will lead the parade from a carriage, alongside his wife Queen Camilla.
His mother, Queen Elizabeth II, rode on horseback for the Trooping the Colour until 1987, when she retired to a carriage at age 61.
After the procession, there will be a Royal Air Force flypast, which the Royal Family will watch from the balcony.
