The Princess of Wales was once so attached to her heavy kohl eyeliner that she refused a make-up artist on her wedding day so that she could stick with her signature look.
In recent years, she's toned down the heavy black rings of eyeliner that attracted criticism from fashion heavyweights Vivienne Westwood and Viktor & Rolf.
But as she welcomed the Nigerian President and First Lady to Windsor for a glitzy state banquet last week, the smoky eye make-up she favoured throughout the 2010s was back with a bang.
At Paris Fashion Week last month, smudged grey eyeshadow and heavy liner was also all over the catwalk, meaning it won't be long before we're all queueing up at Boots for the latest smoky eye palette.
But how can you avoid Kate's mistakes of the past - especially in midlife when sharp lines are not flattering to an ageing face?
As she welcomed the Nigerian President and First Lady to Windsor for a glitzy state banquet last week, the Princess of Wales added an edge to her sophisticated emerald Andrew Gn gown by opting for a dark, lived-in eye maquillage
'Smoky eyes can look incredible at any age, it's all about technique and choosing the right shade,' celebrity make-up artist Joy Adenuga shared.
'On mature skin, the biggest mistakes are going too heavy with dark liner or packing on shadow without blending, which can make eyes look smaller and emphasise fine lines.
'Instead, build colour gradually, focus the darkest tones on the outer corners with a brush such as the smudger brush, and swap harsh black for softer browns or charcoals, it gives definition without looking too much.
'Picking the right shade for your eye colour makes all the difference. For example, Princess Kate has green-blue eyes, and a hint of dark brown really makes them pop.
'Think Victoria Beckham Satin Kajal in Cocoa or Chenel Stylo Yeux in Espresso.
'Over the years, you can see her smoky eye has evolved: she's moved away from heavy, dark tones and now opts for softer shades that enhance her eyes. It's an elegant look that flatters at any age.'
Read on to see which eye make-up mistakes to avoid from the past ten years - as you dabble with the smoky look again...
2010
Kate, pictured in 2010, sporting her signature dark eye make-up while announcing her engagement to Prince William
Lining around your whole eye was all the rage in 2010 - and Kate was very fond of the technique.
While announcing their upcoming nuptials, the royal sported her signature look - heavily kohl-lined eyes, rich tanned skin and defined brows.
2011
The Princess pictured in 2011, at a dinner reception in aid of the National Memorial Arboretum Appeal
In 2011, the royal - who had just wed Prince William in a fairytale wedding - added a smoky shadow to her repertoire.
She accentuated the look by focusing the dark pigment into the crease.
To add a more glamorous flair, Kate also added dark mascara onto her top and bottom lashes.
2012
Kate wore smoky eyeliner in 2012, as she visited Liverpool
The Princess of Wales went for a chunky eyeliner look in 2012, as she visited Liverpool.
Stepping away from a more graphic eyeliner, it appears the royal began experimenting with a more smoky look.
2013
Kate wore dark eyeliner and eye shadow for an engagement in 2013
In 2013, Kate attended a SportsAid Athlete Workshop wearing her signature make-up look.
Seemingly combining the sharp, graphic and smoky eye elements, the royal went for a structured eyeliner all around the eye - and fanned it out with some eyeshadow over the lids.
2014
Kate experimented with eye shadow in 2014
The royal appeared to have channelled a soft wing with eyeshadow as she made a glamorous appearance at the National Portrait Gallery in 2014.
Going for softer hues, she focused on greys and browns for a more 'blended' look than her previous iterations.
2015
In 2015, Kate channelled the popular cat eye trend
In 2015, the more fanned out dramatic cat-eye look started to enter the mainstream.
Kate decided to channel the Parisian trend as she visited Harrow College for Mind World Mental Health Day that year.
However, adding more dimension she popped a dabble of brown/grey eyeshadow on the side of each eye.
2016
In 2016, Kate went for a graphic dark liner around the eyes
Ten years ago, in 2016, the Princess stepped out for an exhibition sporting some very bold, dark eyeliner.
Accentuating her light, hazel eyes, Catherine looks to have gone for a black felt liner around the top of her lid and waterline.
However, adding even more drama to the aesthetic, she also sprinkled some dusky silver eyeshadow.