She's never known to put a fashion foot wrong.
But the Duchess of Cambridge will have to tread carefully to make sure she stays on the right side of the powers that be at Royal Ascot.
Organisers of the exclusive equestrian fixture beloved of the Queen and attended last year by Carole Middleton, are reining in the fillies intent on showing off too much flesh.
The dress code was previously relaxed to make the meet more inclusive – an experiment deemed to have failed.
Spokesman Nick Smith says: "It is stretching a point to say standards have collapsed but there is no doubt that our customers would like to get back to a situation where it is universally acknowledged that this is a formal occasion and not an occasion where you might dress as you would at a nightclub.
"It is probably fair to say that the dress code hasn't necessarily been enforced quite as rigorously as we might have liked."
The new edicts apply to the Royal Enclosure and the area next door, the Grandstand.
Ladies will have to wear skirts of "modest length" that fall just above the knee or longer – meaning Kate who considers her legs one of her greatest assets must cover up.
Her cousin by marriage Eugenie may also consider reviewing her sartorial approach to the races.
And fascinators, those fluttery headpieces that have a starring role in the Duchess' much admired wardrobe, have also fallen out of favour with the course authorities.
"Hats should be worn; a headpiece which has a base of four inches (10cm) or more in diameter is acceptable as an alternative to a hat," state the rules.
The less formal – and more affordable – Silver Ring enclosure will not be affected by the changes.