The Duchess of Edinburgh and her daughter Lady Louise looked equally stylish as they joined other members of The Firm at Trooping the Colour today.

The annual event, a major highlight of the royal calendar, celebrates the birthday of the reigning monarch in the UK and has been held every year for the past 260 years.

Sophie, 59, was dressed for the occasion, donning a bright yellow dress from Beulah London and a Jane Taylor hat, channelling Spring on a rainy day in London. 

She was joined by her daughter, Lady Louise, who looked graceful in a white chiffon tea dress adorned with blue flowers - a frock she previously donned for the King's Coronation last May.

The dress she wore is from Suzannah London and she paired the standout garment with a light blue fascinator and silver pearl drop earrings. 

Lady Louise , 20, who is currently studying at the University of St Andrews, did not attend Trooping the Colour last year.

Her 16-year-old brother, James, the Earl of Wessex, was also absent last year and did not go with his family this year.

It is believed that the teenager is currently sitting his GCSEs, as the exam season ends on June 21.  

Sophie was pictured next to her husband, the Duke of Edinburgh, who looked dapper in his dashing red uniform, displaying his medals. 

Meanwhile, the Princess of Wales and King Charles III were reunited on the Buckingham Palace balcony today for the first time since they both began cancer treatment.

Kate joined members of the Royal Family to watch a spectacular flypast by the RAF as she made a triumphant return to public life at Trooping the Colour. 

And in a sweet gesture from the monarch, Kate stood next to Charles - a change from last year's arrangement when her husband Prince William was next to him. 

The flypast began as senior royals came out onto the balcony - with Charles and Camilla followed by Kate and William and their children George, Charlotte and Louis. Kate then leant over to speak to Charles, who laughed at something she said.

They were joined by the Duke and Duchess of Edinburgh, with the family smiling and waving to crowds before standing proudly as the national anthem was played.

Kate's appearance had been in doubt after she missed the final Trooping rehearsal last weekend, with confirmation that she would attend only given at 6pm yesterday.

But with the King also suffering from cancer, today's spectacle of military pomp and pageantry became a symbolic statement by the monarchy after much uncertainty.

Scotland Yard had a 'substantial' policing operation in place, with anti-monarchy group Republic allowed to protest but banned from using amplified sound.

Hundreds of Metropolitan Police officers were deployed on the ceremonial route to ensure the safety and security of those watching, with tens of thousands gathered.

Earlier, the 42-year-old Princess of Wales beamed and waved as she and her three children, Prince George, Princess Charlotte and Prince Louis, were cheered by crowds on The Mall in a carriage procession for the Trooping the Colour ceremony.

Kate was surrounded by other members of the family - with her husband Prince William , Colonel of the Welsh Guards, on horseback, along with Princess Anne , Colonel of the Blues and Royals, and Prince Edward , Colonel of the Scots Guards.

After spending much of the year coming to terms with the diagnosis and receiving ongoing chemotherapy, Kate looked relaxed as she travelled along one of London's most famous thoroughfares with her family in the glass state coach. 

The family were first seen arriving at Buckingham Palace in a car at 10am, with George sitting between Kate and William, and Charlotte and Louis opposite.

King Charles III also rode in a carriage with Queen Camilla, a departure from last year because of his illness, and he inspected the officers and guardsmen on Horse Guards Parade in Whitehall from the coach rather than from a horse.

Trooping the Colour is a social as well as a ceremonial occasion and the stands overlooking the parade ground were filled with about 8,000 spouses, girlfriends and parents of the guardsmen and officers on parade.

It featured more than 1,250 soldiers, and hundreds of Guardsmen were lined up on the parade ground waiting to be inspected by the King from his carriage with Camilla, Colonel of the Grenadier Guards, and joined by the mounted royal Colonels.

The colour, or regimental flag, that was trooped WAS the King's Colour of number 9 company, Irish Guards.

When the royal carriages finally came to a stop Louis was the first to leave, followed by his elder brother George and sister Charlotte.

Finally, Kate stepped down wearing wearing a Jenny Packham dress, hat by Philip Treacy and the Irish Guards Regimental Brooch, as she is the regiment's Colonel.

When the inspection of the Guardsmen in their scarlet tunics and bearskins began, the King cast his eye over the servicemen who are fighting soldiers when not performing ceremonial duties.

Sat beside him in the carriage was the Queen who wore a pale green silk crepe dress and coat by Anna Valentine, Philip Tracey hat and her Grenadier Guards military brooch.

During the pageantry the colour was first trooped through the ranks of soldiers before the guardsmen marched past the King, first in slow then in quick time with the King acknowledging the command of 'eyes right' with a salute.

For the first time in more than 100 years, soldiers on parade were allowed to have beards.

The rule change, which applies across the Army, was approved by the King earlier this year after facial hair was only allowed for religious, medical or role specific reasons.