Princess Kate is obsessed with a blazer style that King Charles swears by

On Thursday the Prince and Princess of Wales attended a mental fitness workshop run by SportsAid at Bisham Abbey National Sports Centre in Berkshire.

They have spent the week raising awareness about the nation’s mental health, and joined a session which aims to boost the wellbeing of athletes.

During her outings this week Kate has sported a plethora of various outfits, from knitted two-pieces to black and yellow combinations, showcasing her fashion prowess. And for her final appearance, she wore a royal blue blazer in King Charles‘ go-to style.

MORE: Princess Kate just wore the red tweed blazer trend that's trending for AW23

READ: Princess Kate plucks pinstripes out of fashion obscurity

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The Princess wore dark blue skinny jeans (yet another example that the retro trouser silhouette is returning), paired with a white base layer and a double-breasted blazer with gold buttons.

Though a single-breasted blazer is associated with more casual affairs, Kate's father-in-law, King Charles III, has almost always only opted for double-breasted, whatever the occasion.

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Alongside his blazers, the stylish King has notably worn two overcoats on repeat since the 80s: a tweed double-breasted Anderson & Sheppard piece, and a camel-coloured coat with brown buttons.

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When should you wear single-breasted and double-breasted blazers?

There are no set rules for when you should or shouldn't wear one or the other, but a single-breasted blazer is associated with semi-formal occasions, like smart-casual drinks. And double-breasted - an overall more structured and polished silhouette, is often worn for weddings, black tie events etc.

Princess Kate interchanges between the two silhouettes, but has recently proven the power of the double-breasted look for any occasion, showcasing her penchant for modern fashion.

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For today's outing she paired a double-breasted number with a vest and skinny jeans, an outfit where a single-breasted jacket would also suffice. 

Last month during a family portage session as part of her Shaping Us campaign, Kate donned a red textured double-breasted blazer from Zara that is trending for AW23.

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Two days later she effortlessly revived pinstripes in a navy blazer and suit set from royal go-to brand Holland & Cooper, a label known for its exquisite tailoring

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If you're in need of autumn/winter tailoring inspiration, look no further than the Princess of Wales.