Today, the 36-year-old is making her first public appearance since the arrival of her third child, Prince Louis on 23 April 2018.
Naturally, she looks flawless. The mum-of-three arrived at her brother-in-law’s wedding at 11.57am this morning wearing a primrose yellow, wool, silk tailored coat by Alexander McQueen that we may well have seen before.
We know Kate likes to recycle outfits she’s showcased before, and if fans think the Duchess’ look today seems familiar, that’s because it looks remarkably like the McQueen outfit she wore to both Princess Charlotte’s christening and the Queen’s birthday celebrations.
The Duchess accessorised her simple, yet elegant look with a hat with an oversized flower by her go-to milliner, Philip Treacy and shoes by Jimmy Choo.
She also opted to keep her long locks in loose waves.
In her typically tactful style, the Duchess of Cambridge’s outfit carefully walked the line between being notably chic yet understated enough not to upstage the bride.
This isn’t the first time the Duchess has trusted the luxury British fashion label with dressing her for a high-profile occasion.
Kate wore a lace, bespoke gown by Sarah Burton for McQueen for her own Westminster Abbey wedding back in April 2011 and turned to the brand again last May for her sister Pippa Middleton wedding to James Matthews.
Known for her diplomatic dressing, Kate chose a simple yet elegant blush pink Alexander McQueen dress, designed to deflect attention back to her sister, the bride in her lacy Giles Deacon gown. The Duchess also received international acclaim for the floral, off-the-shoulder Alexander McQueen gown that she wore to the BAFTAs in 2017.
There will have been a lot for the Duchess’ stylist Natasha Archer to think about when prepping her outfit for Meghan and Harry’s nuptials today.
Though Kate’s a dab hand at nailing that ultra glam post-birth look on the steps of the Lindo wing, doing it at a huge global event, so soon after welcoming baby number three and under the scrutiny of the world’s gaze is a game changer. Even for Kate.
Given that it has been less than a month since the Duchess has given birth, comfort may have played a role in her outfit choice.
Then there’s the importance of ensuring Kate didn’t wear the same designer as Meghan Markle. One of the designer’s experts speculated the Duchess might turn to is Canadian-born, British-based label Erdem, but as we now know Meghan hasn’t chosen this particular designer for her own dress, but Givenchy.
Erdem is known for their exquisite floral gowns that are perfect for a spring nuptials and it would have been a valid choice for the Duchess considering she has often turned to the designer in the past.
Feeling body confident post third baby may have also influenced the Duchess’ sartorial decision.
“Attending a huge event such as a wedding so soon after giving birth can be daunting for any new mum,” explains Stuart Miles, leading image, style, and ageing expert and founder of MilesYounger.com.
“The Duchess will have been aware of the focus on how she looks and the scrutiny that comes with her role. But she has had some experience of bouncing back after pregnancy and has therefore taken the opportunity to dazzle.”
Without, of course, upstaging.
“Kate looks sophisticated and confident in a chic yellow/cream design by Alexander McQueen which she teamed with a bold hat design by Phillip Treacy,” Stuart says of her outfit choice.
“Demure yet one of the strongest style statements hat wise I have seen her make. It showed a confident Duchess and one who exudes comfort and style.
“She didn’t have to make a strong style statement today but by using a soft, lighter colour she looked understated yet suitably royal.”
Stuart believes the fact that the Duchess will also be on mum duty during the day will have played a part in her outfit choice for today’s nuptials. Indeed we saw Kate helping to guide the bridesmaids, page boys and other mini bridal party into the chapel for the ceremony.
“Kate will have two other children to deal with during the celebration and will need to be hands on at every occasion so anything complicated or flouncy just wouldn’t have worked,” he explains.
So how does the Duchess’ outfit today compare to her other first post-birth appearances?
Just five weeks after giving birth to Prince George, Kate looked every inch the fashionable first-time mum in a floaty, Zara geometric-patterned top, black, skinny, J Brand jeans and her trademark LK Bennett wedges as she attended a Marathon event in Anglesey.
With a nod to her rural surroundings, the new mum completed her post-birth look with a light green tweed jacket from Ralph Lauren.
After Charlotte, the Duchess took a little longer before making her first public appearance at the Anna Freud Centre in London.
Though she looked elegant in a £1,245 dogtooth shirtdress from Ralph Lauren, it was her funky new fringe that stole the headlines.
As today’s outfit is proof, the Duchess certainly gives a good wedding look. Click here for some of her other winning wedding wears.
Read more from Yahoo Style UK: