Burrell, on a trip to Australia to promote etiquette lessons, was browbeaten into backtracking by breakfast television host Karl Stefanovic.
He said in a television interview: “I met Mother Teresa; she had it. Pope John Paul II had it. The Queen has it. Diana certainly had it. Kate doesn’t.”
“She’s a lovely, lovely girl and if you get to meet Kate you will know she totally adores her husband and they’re devoted to each other, but that extra something which you call the X factor, the magic quality, charisma…it’s not there.”
He was lambasted over his comments when he appeared in a second interview yesterday, questioned by Stafanovic on the Nine Network’s Today show in Australia.
Stefanovic, 42, asked: “You said she lacks the X-factor that Diana had. That’s way too harsh isn’t it?”
Burrell replied: “I apologise if that’s been taken out of context but what I was trying to say was Diana was unique and irreplaceable and she had that something, which is charisma, or magic. I’m not quite sure what it is.
“Kate is a beautiful young lady. She’s gorgeous. She’s never put a foot wrong.
“She has the love and support of her husband, and they are the future of the Royal Family.
“I think we should support them, and maybe my comment was out of kilter.”
He added: “I didn’t mean it that way. What I meant was, she is a safe pair of hands. Diana was much bigger.
“Kate wouldn’t want to be Diana, she wouldn’t want to try and fill her shoes. That’s an impossible ask.”
The television anchor then laid into him. “Here is a mother of two who’s doing her very best on the world stage. Wherever she goes she’s got cameras on her.
“She does have the X-Factor: everyone wants to see what she’s doing and she doesn’t put a foot wrong. How dare you even say that?”
Burrell said: “Standing beside someone like Diana, I saw something so special and so magical that I’ve never seen that again in another human being.”
Stefanovic asked: “How often have you stood beside Kate?”
Burrell,59, said: “No I haven’t. I don’t know Kate, I see her the same way you do – through a lens.”
As the encounter got increasingly heated, Stefanovic said: “Come on. Leave her alone.
“If William is King one day and I found out you had said that about Kate I wouldn’t…