It was an iconic moment that came not a moment too soon, one that saw the ever eloquent Duchess of Cambridge splashed across thousands of websites, magazines, Instagram accounts and more.
And before you ask, we're not talking about her royal wedding to Prince William back in 2011.
Nope, one of Kate's most defining, awe-inspiring, downright glorious fashion moments actually occurred on a summers day in 2019 - and if you haven't quite pin-pointed it yet - allow us to indulge you.
On June 18, 2019, Duchess Catherine stepped out at Royal Ascot, the annual racing event that attracts members of Britain's most regal family year on year.
This certainly wasn't the first time the Duchess had attended the prestigious event. Since becoming a member of the royal family back in 2011, we've seen her grace the Ascot greens many a time.
But in 2019, her appearance was a little different - at least, it was for those fashion-fiends among us.
And the reason why? Well, when you take a look at what Kate wore, the reason might just become clear.
Of course, to some of us, you might think the Duchess' blue design for the 2019 event was on par, if not maybe less impressive in comparison to her array of sparkly couture dresses we've seen her wear many a time.
But this was no ordinary occurrence, because when we flocked to quickly find out who the stunning cornflower blue ensemble was designed by, fans were in for a bit of a treat.
The outfit in question was created by none other than Haute Couture designer Elie Saab - and this marked the very first time the Duchess had worn one of his revered creations.
Based in Lebanon, the self titled designer shows his collections regularly at Paris Fashion Week, with his many bridal-esque and red carpet-worthy looks revered and downright drooled upon by the masses.
Being one of the world's most significant fashion influencers, it was well overdue for Kate to don one of the designer's ensembles - and what a glorious moment it was.
There was another element to the outfit that also made it a little extra special.
While the outfit looked like a dress, it was in fact a two-piece ensemble created by the Lebanese designer.
Kate paired it with an angled Philip Treacy hat, Kiki McDonough earrings and Gianvito Rossi heels.
While it was technically summer in the UK at the time, it wasn't all too surprising to see the weather take a bit of a turn (this is England, after all).
And to be honest, we were pretty happy about it, because it gave rise for another iconic moment that we love to see from any royal couple.
Seriously, who didn't gaze fondly at the image of Wills and Kate stood under an umbrella like something out of Mary Poppins?
So with that said, we're quite confident in claiming this was one of Kate's most iconic fashion moments to date.
It's a big call, we know, but you can't argue that it's up there with her 2018 State Banquet look (think Cambridge Lovers Knot tiara combined with that ice-blue gown by Alexander McQueen).
And we can't forget her heavenly pale pink sequined Jenny Packham gown, which she wore in her first red carpet appearance following her royal wedding to Prince William in 2011.
Speaking of, honourable mention must go to her actual wedding dress - the lace long-sleeved design created by Sarah Burton for Alexander McQueen set the precedent for bridal fashion for years, and still does to this day.
What a fashion maven Kate truly is - someone seriously needs to put all of these looks into one place for our viewing pleasure!
Oh wait - perhaps the below might be a good start...