Royal Ascot racegoers will have to meet strict style criteria when they dress for this year's meeting but help will be on hand from a team of specially trained "dress code assistants".
Organisers have raised the bar in the fashion stakes by introducing new rules about attire, including imposing a ban on fascinators in the royal enclosure.
Kate Middleton, the Duchess of Cambridge, is often pictured wearing a fascinator.
Around 300,000 people will flock to Berkshire for the annual horse racing event which starts on Tuesday and there is a chance they will not all be up to scratch so a team of eagle-eyed helpers will be on hand to whip them into shape.
A selection of waistcoats, ties, pashminas and other items will be available at the turnstiles for those who need them.
The new dress code was first announced in January and organisers sent out reminders with badges and tickets.
The decision to tighten and clarify the dress code at the annual summer event and comes amid criticism of sartorial standards which have been more loosely enforced in recent years.
Thousands of visitors who flock to the less formal grandstand enclosure during the week-long meet will also be obliged to adhere to strict new guidelines.
In the royal enclosure, fascinators are no longer deemed acceptable.
The new dress code states: "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."
Women will also be expected to wear skirts or dresses of "modest length" which fall just above the knee or longer. This clarifies previous guidance which stated miniskirts were "considered unsuitable".
For men, black or grey morning dress with a waistcoat and tie are now compulsory in this area of the course and cravats will not be allowed. A black or grey top hat and black shoes must also be worn.
In the grandstand, which is open to the public and subject to less stringent rules, a hat or fascinator will be compulsory for women.
This marks a significant change to previous years, when female race-goers were simply advised that "many ladies wear hats". Strapless or sheer-strap tops and dresses will be banned.
For men, a suit and tie will now be imperative.
The less formal Silver Ring will not be affected by the changes.
Charles Barnett, chief executive of Ascot, said: "Ascot is Europe's flagship race meeting and one of the world's greatest sporting and social events. We have tried to provide an appropriate dress code that is clear, workable and in line with the wishes of racegoers.
"Over the last few months, a huge amount of planning has gone in to making sure that the implementation of the new code goes as smoothly as possible. During the meeting itself, our team of special dress code assistants will help people with any queries that they may have."