In his first interview since the birth of Prince George on July 22, William said he and Kate were enjoying their new role as parents.
The Duke told CNN: “He’s a little bit of a rascal, I’ll put it that way.
“He either reminds me of my brother or me when I was younger, I’m not sure, but he’s doing very well at the moment.”
William described George as a “little fighter”.
“He kind of, he wriggles around quite a lot,” he said. “And he doesn’t want to go to sleep that much, which is a little bit of a problem.”
The Duke admitted he does not get up in the night to see to the baby as much as Kate, adding that she is doing a “fantastic job”.
William said he believes fatherhood has changed him already.
“I think the last few weeks for me have been just a very different emotional experience,” he said.
“Something I never thought I would feel myself. And I find, again it’s only been a short period, but a lot of things affect me differently now. “
Asked about the moment he and Kate brought George out of St Mary’s Hospital in Paddington, central London, for the first time, William said they were “happy to show him off to whoever wanted to see him”.
“I think I was on such a high anyway,” he said. “As any new parent knows, you’re only too happy to show off your new child and, you know, proclaim that he is the best-looking or the best everything.
“It’s nice that people want to see George, so, you know, I’m just glad he wasn’t screaming his head off the whole way through.”
William said he was “terrified” he would mess up fixing the baby’s car seat into the back of the vehicle in front of the world’s press and admitted he had practised the manoeuvre.
He said: “I know there’s been speculation about that. I had to practise, I really did. I was terrified that I was going to do some... you know, it was going to fall off or it wasn’t going to close properly.
“So, I had actually practised with that seat, but only once before.”
William said it was important to him to be able to drive his family away from the hospital.
“Where I can be, I am as independent as I want to be. And same as Catherine and Harry,” he said.
“We’ve all grown up differently to other generations. And I very much feel if I can do it myself, I want to do it myself. And there are times where you can’t do it yourself and the system takes over or it’s appropriate to do things differently.
“But I think driving your son and your wife away from hospital was really important to me. And I don’t like fuss so it’s much easier to just do it yourself.”
The Duke, who looked casual in a navy blue polo shirt bearing the logo of the Tusk Trust, of which he is a patron, said he was “headstrong” about things he believed in.
Asked if he was doing things his own way as second in line to the throne, he said: “I’m just doing it the way I know this, you know. If it’s the right way, then brilliant. If it’s not, if it’s the wrong way, then I’ll try to do it better.
“I’m reasonably headstrong about what I believe in, and what I go for, and I’ve got fantastic people around me who give me great support and advice.”