Kate, 41, looked “absolutely stunning” in a turquoise coat that matched the colour of the 1st Battalion Irish Guards’ blue plume, said royal biographer Angela Levin.

The Princess of Wales received her first salute as the new Colonel of the Irish Guards taking over from Prince William as colonel on Friday.

The royal commentator also found her taking over the new role as “absolutely moving” as Williams had taken over from his father.

Ms Levin told GB News: “The way he passed it over, the way he looked at her. What she dressed like was absolutely stunning.”

During her emotive speech, the princess said: “I really couldn’t be prouder to stand in front of you here today. It really is a true honour to be your Colonel. I am here to listen to you, to support you, and to champion you in all you do – this is a responsibility I do not take lightly.”

Meanwhile, William said that being Colonel of the Irish Guards has been one of the “great honours of my life”.

Kate dressed in an emerald green outfit with matching heels and had given sprigs of shamrock to the officers and guardsmen, as well as the Irish wolfhound regimental mascot Seamus.