Kerry said: “I am a republican, but I thought it was the young royals that were saving the royal family.
“There is a lot of affection for Will and Kate and there was previously a lot of affection for Meghan and Harry.
“So when I saw that request he made, I thought it was just another up yours to the Queen by Harry.
“I’m amazed that a young man who purports to have such a strong bond and love for the Queen would be doing these sorts of things.
“What does he get out of it? If he wants to be one of the people, fine but I don’t think anyone will ever think he is one of the people.
“He has lost the plot, I think. I don’t think it’s Meghan who is driving this agenda. I think it’s Harry.
“I think he has decided he wants to have his own life, and to the hell with the rest of you.”
Harry was snapped yesterday exiting Abbey Road Studios in London on Friday with rocstar Jon Bon Jovi.
The music legend and the royal have teamed up to raise money for wounded servicemen and servicewomen in the Invictus Games.
A brief video showing a nervous Harry standing in front of a microphone with Bon Jovi listening carefully to the instructions given to him by the rock star was released on Harry's official Instagram page, @SussexRoyal.
"So of course all eyeballs are going to be on there.
"I expect the Royal Family to have game faces on.
"It is going to be business as usual."