Kate Middleton stuns as she joins the Queen and European royals at Knights of the Garter ceremony in Windsor

KATE stunned in all white as she joined the Queen and European royals at the Knights of the Garter ceremony today.

The Duchess of Cambridge dazzled in the £250 dress at the annual service at Windsor this afternoon.

The 37-year-old wore a '50s ivory coatdress with cropped jacket "panels" with fine black lace by Catherine Walker.

She was joined by Queen Letizia of Spain, Queen Maxima of the Netherlands and the Duchess of Cornwall for the annual service.

They appeared all smiles as they supported their husbands, King Felipe VI of Spain and King Willem-Alexander of the Netherlands as they were officially invested Knights of the Garter by her Majesty.

Her Majesty and the Garter Knights wore their blue velvet robes and black velvet hats with white plumes.

The Queen was joined by the Prince of Wales, Duke of Cambridge and other senior royals in St George's Chapel at Windsor Castle at the service.

The Order of the Garter is a 700-year-old tradition that was founded by Edward III in 1348.

It recognises the contributions of public service from those lucky to be honoured by the Queen - typically Lords and Ladies in the UK.

The Order has a limit of 24 members, excluding The Queen and the Prince of Wales, foreign royals have been given "Stranger Knight" status since 1813.

"Stranger Knight" is a second order bestowed upon foreign royals.

In the past a controversial recipient was Kaiser Wilhelm of Germany before World War I.

The last time a "Stranger Knight" was in vested was King Harald of Norway in 2001.

Royals often keep the honour during their reign and then pass the title to their successor.

Other foreign royals who are currently "Stranger Knights" are Queen Margrethe of Denmark, King Carl Gustaf of Sweden, former King Juan Carlos of Spain, Princess Beatrix of the Netherlands, King Harald of Norway and former Emperor Akihito of Japan.

Knights of the Garter are chosen personally by the Queen for helping her either in her personal live or by contributing in a particular way to national life.

The appointment is considered a gift and the Queen makes her decision without consulting ministers.

Two official appointments were made today as Lady Companion, Lady Mary Peters, and Knight Companion, Robert Gascoyne-Cecil the Marquess of Salisbury were invested by the Queen.

Lady Mary is a former Lord Lieutenant of Belfast and the Marquess of Salisbury is a former leader of the House of Lords.

Hundreds of spectators saw the Garter Knights walking through the grounds of Windsor Castle.

Their route was lined by troopers on foot from the Household Cavalry's Life Guards and Blues and Royals, wearing their plumed helmets and carrying swords.

The Queen arrived by state limousine.

The royal women made sure to dazzle during today's historical engagement.

They all looked stylish in wide-brimmed hats, with Kate wearing a Catherine Walker coat and Lock & Co hat, while Camilla was dressed in an Anna Valentine coat and Philip Treacy hat; Sophie wore a Suzannah dress and Jane Taylor hat.

The Spanish royal wore a £250 dress by Spanish label Cherubina as her Dutch counterpart wore a pale pink dress.

Queen Maxima wore an outfit by Claes Iversen and a hat by Fabienne Delvigne.

She seemed the most excited by the events, smiling broadly as her husband Willem-Alexander walked past next to his Spanish counterpart Felipe.

The ceremony also marked what is believed to be the second time Kate and Queen Letizia met.

Two royals that were missing today were Prince Harry and his wife Meghan Markle.

The Duke of Sussex has not been invested himself, but he attended an event today about continuing his mum Princess Diana's work on ridding landmines from Angola.

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