King Charles III has taken part in his first Trooping the Colour since becoming monarch.

Princes Louis and George and Princess Charlotte joined other royals on the Buckingham Palace balcony to watch a flypast in honour of their grandfather's official birthday.

In a surprise tribute, airplanes were used to spell out the King's initials, CR.

Thousands watched the event at Horse Guard's Parade and the Mall in London.

The royals watched an extended military flypast after the display on coronation day had to be scaled down due to bad weather.

Around 70 aircraft from the Royal Navy, British Army and Royal Air Force took part - including aircraft from the Battle of Britain Memorial Flight, the C-130 Hercules on its final ceremonial flight, modern Typhoon fighter jets with a red, white and blue finale from the Red Arrows.

A sea of mobile phones were spotted among the crowds, with many holding them up in the air to capture the moment.

The Trooping the Colour is part of the annual calendar of big royal events and for the first time, it was with King Charles in the leading role.

There may have been a moment of poignancy for the King too. Just a year ago, at the Platinum Jubilee, it had been his mother on the same balcony, appearing before the crowds.

The King took has part in his first Trooping the Colour as monarch on horseback.

The King's horse appeared to be a little skittish at the start, but calmed down as the event went on.

It is the first time a monarch has ridden on horseback at the event in 30 years, when the late Queen rode her horse, Burmese, in 1986.

He was joined by the other royal Colonels on horseback - the Prince of Wales and the Princess Royal.

The Duke of Edinburgh also rode during the ceremony in his role as Colonel of the 1st Battalion London Guards.

The ceremony started at Buckingham Palace, with the King and senior royals travelling down The Mall towards Horse Guards Parade.

The colour - or regimental flag - was then trooped in front of hundreds of Guardsmen and officers from the 1st Battalion Welsh Guards.

There was music and marching while the King carried out an inspection of the soldiers - moving slowly along the line as they stand in formation.

After he coursed through the Mall, the King received the royal salute as the Colonel-in-Chief of the Household Division's regiments.

The senior royals on horseback were joined by the Queen, the Princess of Wales and her children, Prince George, Princess Charlotte, and Prince Louis, who travelled in a carriage to support their grandfather.

Prime Minister Rishi Sunak was spotted in the crowd, as well as Labour leader Sir Keir Starmer, along with prime ministers of Commonwealth states and realms.

One royal fan said they were "so happy" to be at Trooping the Colour after missing out on the King's Coronation.

They said: "We're so happy about coming today. We've been bringing our kids to see all of the pomp and ceremony for years.

"We've been exchanging photos, and we've got plans for birthday cocktails later."

Before the ceremony began, the Prince of Wales paid tribute to those took part in last week's rehearsal in soaring temperatures, which reached 30°C (86F) in London.

The last time a monarch was on horseback was when chart toppers included Wham! and Doctor and the Medics.

Following the parade, troops fired a 41-gun salute in Green Park to mark the King's official birthday - while from the Tower of London the Honourable Artillery Company fired 62 volleys.