Prince William Speaks Movingly About How Fatherhood Has Changed His Life

— -- In a very candid interview to air Monday, Princes William and Harry opened up about what they've learned from their father, but also made very personal revelations about their family, fatherhood and the friendship the two brothers share.

The princes sat down at Kensington Palace for the a documentary celebrating 40 years of Prince Charles' charity The Prince's Trust.

Prince William, 33, spoke movingly about how fatherhood has changed his life.

"I'm a lot more emotional than I used to be, weirdly. I never used to get too wound up or worried about things," he said, as he discussed how his children Prince George and Princess Charlotte have affected him.

The death of Prince William’s mother Princess Diana when he was just 15 seemed to weigh heavily on his mind as he told the presenters that as a parent he has realized how "precious life is."

"But now the smallest little things, you well up a little more, you get affected by the sort of things that happen around the world or whatever a lot more, I think, as a father," William said.

"Just because you realize how precious life is and it puts it all in perspective, the idea of not being around to see your children grow up and stuff like that," he said.

William and Harry grew up with Charles and Diana in Kensington Palace and now both make their homes as neighbors. Harry, 31, clearly relishes his role as uncle to Prince George and his baby sister Princess Charlotte, describing their home as a "giant playground" for his nephew and niece.

"I can hear the wheels of those plastic tractors Prince George loves playing on," he said.

William teased his younger brother, saying, "He comes and scrounges food," showing that even though he has his own family now, Harry is still a big part of their life.

William and Kate have wanted to provide their children with as normal an upbringing as possible. They recently announced that George will start nursery school at a Montessori school for local children near their country home in Norfolk, and William referred to the importance of his upbringing by Charles and Diana.

"I remember our mother and father taking us to charities and showing us what goes on," he said. "I think seeing such a broad spectrum from a young age is important."

Clearly William and Kate are attempting to model those life lessons as the raise their own kids.

"You don't just live in a palace," the prince said. "It's very important you get out and see what goes on in the ordinary world."

The documentary was shot over the last year with British presenters Anthony McPartlin and Declan Donnelly, better known as Ant and Dec, shadowing Prince Charles as he went about his life. The result is a rare glimpse in the world of Prince Charles, what motivates him and his tireless work on behalf of his charity The Princes Trust.

Prince William told the filmmakers it was his father's devotion that most impressed him.

"He's incredibly driven to do his duty. It's where a lot of his passion and drive come from. I think he relishes the challenge but equally he's had such a difficult time getting across his points and his issues.

"For whatever reasons they might be, I think it's a real credit that's he’s managed to keep going as he has," he said. "I really respect and look up to him for that, because it can't be easy to have taken so many knocks over the years and still keep going and fighting as much as he has."

And rather than calling him Dad, Daddy, or Father the young princes refer to him as Pa.

Harry reflected on the advice he often gets from his father.

"The advice that he can give us based on the context that he’s made over the years is incredible. You can actually ring him up and say I'm in a bit of a pickle here or even better you can offload stuff," Harry said. "You just say, 'Pa, can you do this?' and he will, he's guaranteed to have one or two people who are specialists in that area and he gets things done."

The documentary also shows rare footage of a young Prince Charles being tickled by the queen and has access to other moments where cameras never ventured before.

Charles, 67, spoke about the joy of being a grandfather, joking he hasn't changed diapers yet, but "I hope there's someone in my old age to keep an eye on me when I'm tottering about."

The Prince of Wales concludes saying he hopes his sons will take over the Princes Trust one day.

"That’s what I hope, that one of them will take interest, because I'm probably getting past my sell-by date now," he said.

The documentary "When Ant and Dec Met the Prince: 40 Years of the Princes Trust" airs Monday on ITV.