The Princess of Wales made a poignant tribute to her late mother-in-law, Princess Diana, with her outfit choice at Trooping the Colour today.Kate, 44, put on a typically elegant display in a light blue and white Catherine Walker coat dress and a matching Philip Treacy hat during the King's official birthday celebrations.Eagle-eyed royal fans will no doubt notice that Kate's tailored coat dress, called Lafayette, bore a striking resemblance to one sported by husband Prince William's mother multiple times throughout the 80s.Diana's version, also a light blue shade with a white trim, featured similar details and was also made by Catherine Walker, which she famously wore during Prince William's first Easter service in 1987.During the Easter event, Diana twinned with the then-four-year-old William, who also wore a similar pale blue Catherine Walker design for church at St George's Chapel in Windsor Castle.Catherine Walker was a go-to fashion house for her, and the Princess of Wales has followed suit in recent years, regularly stepping out in bespoke pieces from the British label.The Lafayette is described by the brand's website as an 'impeccably tailored, hand-crafted couture coatdress defined by precision.'The silhouette is elongated and sculpted through the bodice, with sharp, structured shoulders and clean princess seams that contour the waist before falling into a graceful, fluid midi-length skirt.' Princess Diana and her eldest son, Prince William, then four, both wore a blue Catherine Walker design when attending the Easter service at St George's Chapel in Windsor Castle in 1987 (pictured together with Peter Phillips)It's not the first time Kate has channeled Diana at Trooping the Colour, and at last year's parade, the mother-of-three donned a striking white and turquoise coat dress echoing one of her most memorable looks from the early '90s.Fans were quick to draw comparisons between Kate's refined ensemble and the tailored Catherine Walker suit worn by Prince William's mother during her official visit to New Delhi in 1992.Both outfits featured the same crisp white and turquoise colour palette and sleek silhouette, evoking the timeless elegance that defined Diana's style legacy.The visual tribute didn't stop at the clothing. In a detail that delighted royal fans, Kate also opted for a cherished accessory with a storied royal provenance - the Bahrain pearl drop earrings, originally gifted to the then-Princess Elizabeth in 1947 by the Hakim of Bahrain as a wedding present.The jewellery, which features a diamond stud and suspended Art Deco-style diamonds ending in two Bahrain-sourced pearls, has become a symbol of royal continuity across generations.Diana was the first to wear the earrings after the Queen, having borrowed them as early as 1982 - a year after she herself became a royal bride.She often paired them with the Queen Mary's Lover's Knot Tiara, a piece now closely associated with the Princess of Wales, who continues to wear the tiara at formal state occasions.Kate has worn the pearl earrings several times since Queen Elizabeth II's passing in 2022, signalling both personal respect and royal tradition. The Princess of Wales looked typically elegant in a Catherine Walker coat dress at Trooping the Colour Catherine sat next Prince Louis during the carriage ride, who complemented his mother's coat dress by wearing a tie in a matching shade'Pearls are one of the very few jewellery items you can wear in mourning and are inextricably linked with Queen Elizabeth and her personal jewellery legacy,' royal jewellery expert Bethan Holt previously told People.The nod to both Diana and the late Queen was widely interpreted as a deliberate gesture, designed to underline the Princess of Wales's role as a bridge between the monarchy's past and future.Kate's decision to wear Catherine Walker for such a high-profile event was no surprise.She has often gravitated towards the label's sleek tailoring and understated colour palettes, much like Diana before her.Trooping the Colour is one of the most significant ceremonial events in the royal calendar.Dating back to the 17th century, the annual parade marks the Sovereign's official birthday and showcases the full spectacle of British pageantry.The event features over 1,400 soldiers, 200 horses, and 400 musicians, culminating in a Royal Air Force flypast watched by senior royals from the Buckingham Palace balcony.More than just a spectacle, Trooping the Colour serves as a public reaffirmation of the monarchy's continuity and presence - a role Kate is increasingly stepping into with grace and poise.