Another added: “Catherine Walker coat dress in ‘deep aquamarine’ is how the designer describes it.”

A third observer commented: “I don’t think that is green, looks more turquoise, but I guess we will know for sure later on!”

Others were more blunt, with one royal fan writing simply: “Green???” while another corrected media reports with a one-word response: “Blue.”

One more viewer chimed in: “I’d say it is aquamarine.”

Coordinated Family Look

Kate, 43, completed her look with a blue hat by milliner Juliette Botterill, as well as the Irish Guards Regimental Brooch and a pair of earrings that once belonged to Queen Elizabeth II.

Her daughter Princess Charlotte, 10, also matched her mother’s outfit in shades of blue and white. She accessorized with a small horseshoe-shaped brooch—a sentimental piece that once belonged to the Queen Mother and was passed down to Charlotte by Queen Elizabeth II. Charlotte was first seen wearing the heirloom during Her Late Majesty’s funeral in 2022.