put her best fashion foot forward at , in a stunning in a Catherine Walker design which echoed a look once worn by . The Princess of Wales , dressed in a striking turquoise and white ensemble.

Kate, 43, was joined by her three children - , 11, , 10, and , seven - while rode on horseback, accompanied by and the during the parade.

The royal wore a tailored turquoise coat dress by her go-to designer, Catherine Walker, a favourite of the late . She completed the look with a Juliette Botterill hat, the Irish Guards Regimental Brooch, and reportedly worth £20,000.

Kate's ensemble resembled a look characterised by Diana back in 1988, when she celebrated the official birthday of the late .

The late Princess wore a striking emerald green and white ensemble by Catherine Walker, featuring a tailored jacket with bold white lapels and a matching wide-brimmed hat.

She accessorised with pearl earrings and a signature multi-strand pearl choker, creating a confident and elegant look that blended modern style with royal tradition.

who is an international celebrity and red carpet stylist, exclusively explained to the Daily Express that Kate's outfit was poignant and paid a thoughtful tribute to Macmillan Cancer Support,

She said: "Green is undeniably the colour of Macmillan. With and both undergoing health challenges, this can be perceived as a beautiful tribute to the charity and the vital work they do. It's subtle, but it's deliberate in projecting a united front of support."

Both Princess Kate and her husband, Prince William, are joint patrons of Macmillan.

In March 2024, Kate publicly shared that she had been diagnosed with cancer following major abdominal surgery just months before in January.

Although the initial surgery was believed to be for a non-cancerous condition, subsequent tests revealed cancer, prompting the start of preventative chemotherapy.

The charity is known for providing a wide range of support services to people affected by cancer, including emotional, practical, and financial assistance.

Rebecca added: "Princess Kate's look is iconic. The silhouette is polished and elegant; the vivid aquamarine Catherine Walker coat coatdress was the perfect choice, dignified and regal, and yet the shape and cut feel modern.

"Perhaps the outfit's most compelling element is a clear homage to Princess Diana; I can imagine Diana wearing this look with the same confidence. Catherine Walker was also Princess Diana's favourite designer," she continued.

Meanwhile, Kate and Princess Charlotte sweetly coordinated, which also "echoed" Diana's look nearly four decades ago.

She added: "This intentional matching with her daughter Charlotte echoes another Catherine Walker design Diana and 4-year-old Prince William wore to an Easter church service in 1987 with the Royal Family. It's intentionally iconic; even the choice of colour is legendary. Visual similarities here see a future leader in training."