The color of her outfit is actually called St. Patrick's blue.
Kate wore a Catherine Walker & Co coat dress with a matching fascinator and heels in the St. Patrick's blue hue.
William gave a speech saying it was his 13th and final St. Patrick's Day as Colonel and he was proud of the title.
Kate spoke about being proud to be their Colonel and looking forward to supporting and championing them.
Kate's responsibility as Colonel is to listen, support, and champion the Irish Guards.