Kate joined the Royal Family in 2011 when she married Prince William.
She has since shown off her designer wardrobe and will often recycle many of her outfits.
The Duchess will also often add pieces of jewellery to her looks, from both high-street and designer brands.
Speaking to Express.co.uk, Lucy Ansa-Addo, Director of Laoxa Ltd, explained that the Duchess “respectfully” follows tradition where she can.
She said: “Kate beautifully rocks high end garments and high street designs from Zara, ASOS and GAP.
“She always looks chic and elegant – effortlessly dresses to impress.”
The expert added that Kate’s overall style is “regal”.
Lucy went on: “The Duchess still respectfully follows tradition where possible with her style by wearing pearl earrings for more formal events and engagements.”
The Queen rarely appears without her famous three-strand necklace and pearl earrings, which are now considered part of her royal uniform.
The royal ladies, including Camilla, Duchess of Cornwall and Sophie, Countess of Wessex, have also been seen wearing pearls over the years.
Some of these pieces are heirlooms while some pieces Kate wears are from high-street brands.
Princess Diana also loved pearl jewellery when she was alive, wearing it mostly for formal occasions.
However, although the Duchess will add pearls to her look, the expert explained that she adds a modern twist depending on the occasion.
Lucy added: “The Duchess stuns even more when she is channelling Princess Diana or paying homage to her through her signature styles.
“Adopting the same hues, details and silhouettes.”
The expert said: “We love when Kate dresses down in casual wear from jeans, sneakers, sweaters and t-shirts.
“Although the Duchess is known for stunning dresses and her chic style – it’s always great to see her in more relaxed clothing.
“Motherhood is most likely the reason for this and of course for a much more practical look – she becomes more relatable.
“Kate’s style has become more sophisticated, more chic since becoming a royal.
“We still get to see elements of her previous style – but a more polished version, which we love to see and look forward to seeing more.”
Source: EXPRESS CO UK