And much like Hepburn's iconic white lace dress and swooping feathered hat, Royal Enclosure guests must follow strict fashion protocol -- or risk being turned away.
The plush enclosure has the strictest dress rules on the race course -- women must wear hats, or failing that, a headpiece with a 10 centimeter base. Fascinators -- small ornaments attached to a headband -- are a no-no.
As are strapless, off-the-shoulder and halter neck tops. All straps must also be at least one inch thick.
Likewise, men are required to wear waistcoats, ties, and top hats.
In comparison, the Silver Ring Enclosure, which offers $45 daily tickets, simply requires its race goers to wear smart clothes, with a reminder that "bare chests are not permitted at any time."
Dating back to the 1820s, the Royal Enclosure was originally a two-storey stand commissioned by King George IV, with only those receiving a personal invitation from His Highness getting a look-in.
Such was the exclusivity of the enclosure, it was only in 1955 that divorcees were allowed to enter.
"Its charm is that it's so steeped in history," said Smith. "It started as a very private affair for the royal family -- basically an individual stand with a viewing garden."
"Today it's much more than a single entity -- there are the grandstands, marquees, private boxes. You will probably see the Queen there -- Her Majesty has her own official guest pen (enclosure)."
So what would the Queen have made of Hepburn's outburst? One can only guess Her Highness would not have been amused.