Royal Ascot is upon us, and the royals are out in force

Royal Ascot is ostensibly about horse racing, but you'd be forgiven for thinking it centred entirely on Queen Elizabeth and her colourful outfits.

Held at Ascot Racecourse in Berkshire, the event brings the royals out in force every year, with everyone from Princess Anne to 'Fergie' dusting off their fascinators.

In fact, it might be the ultimate royal-watching event; unlike Trooping the Colour and Christmas, Royal Ascot stretches over several days.

Day One of this year's event kicked off on Tuesday, with Her Majesty joined by Prince Charles, Camilla, Duchess of Cornwall, the Duke and Duchess of Cambridge, the Duke of York, Princesses Beatrice and Eugenie, the Earl and Countess of Wessex, Princess Anne and Zara Tindall.

Royal fans will recall the Duke and Duchess of Sussex attended Royal Ascot last year, marking Meghan's debut at the event.

However, the couple were not present on Tuesday, likely because the Duchess is on maternity leave, having welcomed the couple's first son Archie last month.

As per usual, the Duchess of Cambridge commanded the fashion spotlight.

Catherine, 37, turned heads in a cornflower blue Elie Saab dress with a 'pussy bow' neckline and sheer sleeves, teamed with a matching Philip Treacy hat.

Blue was the colour of the day, also worn by the Queen, Beatrice, Eugenie and Zara.

Camilla, Duchess of Cornwall and Sophie, Countess of Wessex both opted for pale pink, while Anne, Princess Royal went for pale yellow tones.

It wasn't just British royalty on display, however.

King Willem-Alexander and Queen Maxima of the Netherlands also attended, arriving in a carriage with the Queen herself.

The couple travelled to the UK earlier this week for Garter Day at Windsor Castle, where the King was invested into the prestigious Order of the Garter by Her Majesty.

When it comes to headwear, Queen Maxima may have eclipsed her British counterparts, wearing a large hat with striking floral decorations.