She has been in the public eye for almost two decades, blossoming from a shy teenager to one of the most photographed women in the world.
Now, as Kate, the Duchess of Cambridge turns 40, we look back on some of her most iconic moments.
That dress at that fashion show
Although they were in the same friendship group at St Andrew’s University, it wasn’t until William saw Kate in THAT see-through dress (actually a £40 skirt she’d hitched up to her chest) at a charity fashion show that he began to think they may be more than just friends.
The month was March 2002 and as she made her way down the catwalk, William apparently turned to a friend and whispered: "Wow, Kate’s hot!". The rest is history.
Beaming in blue
When the couple announced their engagement in November 2010, Kate chose a dark blue Issa wrap dress, which perfectly matched the beautiful sapphire and diamond engagement ring first worn by Princess Diana.
This outfit was the first of many to create a ‘Kate effect’ when the dress sold out quickly.
In fact, the fashion label actually went into administration after struggling to cope with the unprecedented demand. It relaunched in 2015 but now sells clothes through House of Fraser.
Naturally, all eyes were on Kate when she became a royal bride on April 29, 2011 and she didn’t disappoint.
With its high lace neck, long sleeves and full skirt, her Sarah Burton for Alexander McQueen dress was instantly compared to the elegant lace wedding gown worn by actress Grace Kelly, when she married Prince Rainier III in 1956.
Kate had wanted to combine modern fashion with royal tradition. The lace – made by the Royal School of Needlework – featured flowers from all four nations in the UK – the English rose, the Scottish thistle, the Irish Shamrock and the Welsh daffodil.
A new mum moment
It was a moment the world had been waiting for – the birth of a new king.
When Kate appeared on the steps of the hospital after giving birth to Prince George in July 2013, she wore a simple Jenny Packham shift dress in baby blue and mid-height beige heels.
Years later, she admitted how nervous she felt about facing the world’s press after becoming a mother for the first time.
When asked by author and podcast presenter Giovanna Fletcher was it was like, Kate replied: "slightly terrifying, I’m not going to lie!"
Everything she touches...
Kate chose a Jenny Packham light lemon number and Jimmy Choo nude heels for her moment in the spotlight having given birth to her daughter Charlotte in May 2015.
The ‘Kate effect’ took hold once more with eBay reporting that sales of yellow dresses increased by 58 per cent after this photograph was taken.
Along with her husband Prince William and brother-in-law Prince Harry, Kate launched a mental health campaign ‘Heads Together’ in 2016.
They took part in a documentary and gave speeches, encouraging more people to talk about their mental health.
A year later, Prince William revealed that it was Kate who was the brainchild behind the campaign: "It was Catherine who first realised that all three of us were working on mental health in our individual areas of focus," he said.
A nod to Diana
In April 2018, Kate opted for another Jenny Packham design after giving birth to her third child, Prince Louis.
The bright red dress with white collar was thought to be a respectful nod to her late mother-in-law Princess Diana. The dress was very similar to the one Diana wore when she introduced Prince Harry to the world in 1984.
Kate pays her respects
Quietly and without any fanfare, Kate was spotted in the crowds attending a vigil in South London to lay flowers and pay respects to Sarah Everard, the young woman who was brutally murdered by a serving police officer last year.
It was an important moment for women everywhere to see that Kate wanted to show unity. "She remembers what it felt like to walk around London at night," said one source. Another said: "She felt it was really important to be part of the moment because she felt really emotion about it herself".
A golden Bond girl
Kate blew away onlookers when she appeared at the world premiere of the 25th Bond film at the Royal Albert Hall in September 2021.
Wearing a glittering gold Jenny Packham cape gown, she prompted praise even from James Bond actor Daniel Craig who said: "You look jolly lovely".
Royal experts suggested that the glittering outfit was Kate’s way of help boost the profile of the premiere, which had been delayed for many months due to the pandemic.
Hitting the right note
Despite being one of the most famous women in the world, Kate still manages to keep some secrets.
At Christmas she surprised everyone by appearing alongside singer Tom Walker, accompanying him on the piano as he sang a previously unheard Christmas song at a community carol service at Westminster Abbey.
The singer-songwriter said he was approached by the duchess after they met at a charity event. "We got together, we rehearsed the song like nine times and by the end of it, she’d absolutely nailed it," he said.
Watch: Kate at 40: Duchess' 'commitment' praised on milestone birthday