Queen Elizabeth's Hat Maker Shares Why This Year's Royal Ascot Style Change Is 'Cool'

Queen Elizabeth is halfway through her favorite event of the year: Royal Ascot — and she’s been modeling her signature hats for the occasion!

The five-day event, which started on Tuesday and has been attended by Queen Elizabeth since 1962, has become so synonymous with fashion that many guests plan their outfits six months in advance.

“Everyone makes a wonderful effort, and it’s just fantastic,” Rachel Trevor-Morgan, hat maker to the Queen, tells PEOPLE from her London atelier. “Some people get a bit [worked] up about the rules, because there are strict rules at Ascot, but I think that’s really what makes it what it is.”

This year, for the first time ever, organizers have said that guests can choose whichever gender dress code they most identify with. So, can we expect to see women in hats in the style of Cara Delevingne, who wore a top hat and tails to Princess Eugenie’s wedding? “I think we might see a few, actually,” says the British hatmaker, adding. “I think it’s pretty cool, and it’s a clever way of moving things on without taking away the formality.”

Traditionally, the “rules” dictate that ladies in the Royal Enclosure must wear a dress or skirt “of modest length defined as falling just above the knee or longer.” Dresses and tops should “have straps of one inch or greater” and hats should be worn at all times. Fascinators are not permitted, but headpieces are allowed as long as they have a “solid base of 4 inches or more.” Jumpsuits past the knee are allowed, as are trouser suits so long as they are full-length and of “matching material and color.”

The Queen opted for hats by Trevor-Morgan on Wednesday, but the designer never knows exactly which look she’ll choose until the monarch steps out.

“Sometimes she wears something that we have seen before, which is very nice and a great compliment,” says the milliner, who has been making hats for the Queen since 2006 and whose hat the monarch recently wore for Donald Trump’s visit. “Everyone gets so excited about seeing her and seeing what she is wearing.”

Having designed and handmade approximately 120 bespoke hats for the much-anticipated event — which ends on Saturday — Trevor-Morgan and her team have worked late into the night to complete the vast number of orders, some of which come in before Christmas.

“In a way, your whole year leads to Ascot,” says the milliner, who was awarded a Royal Warrant in 2014. “It’s such a big occasion. I think it’s nice that people want to go for more rather than less because it is Ascot — and if you hold back, you will regret it!”