Prince William and Prince Harry Adore Their Dad and Can't Help Showing It

William and Harry have clearly learned a huge amount from their dad, and the one thing they both really appreciated was how Charles had let them develop their own ideas and become their own people.

"He's done an amazing job, without telling us what we should be doing or the direction we should go in," Harry said on the show.

And they want to hang on to him for as along as possible, too. William told the show he wants his dad to slow down so he's around for decades to come.

One of the funniest revelations in the new program was that Prince Charles has brought his sons up with a habit that leaves both their wives scratching their heads. As William and Harry praised the Prince of Wales for his long time campaigning on environmental matters, they admitted he had always made them turn the lights off whenever they thought extra bulb power wasn't needed to save energy. And Harry added "my wife certainly goes, why are you turning the lights off?" before letting Meghan and the rest of us know that it's because Pa has this one sorted.

The princes opened up about how their dad used to make them go pick up litter during their Summer holidays, and they think it's the best thing ever. Charles made William and Harry clear up after others during a childhood break in Norfolk, and the Duke of Sussex revealed that since then, he has seen it as totally normal to pick up litter.

They both spoke proudly of how Charles has been completely committed to environmental causes for decades, even when others thought he was talking nonsense, and they heaped praise on their dad for having the courage of his convictions and trying to change the way everyone treats the planet.

It was one of the most heartwarming royal moments of 2018. When Prince Charles stepped in to walk Meghan Markle down the aisle on the day she married Prince Harry, it was clear how much the gesture meant to the bride and her soon to be father-in-law.

During the program, Harry confirmed just how special that whole part of the ceremony was to everyone involved, adding that his dad hadn't thought twice about accompanying Meghan on that big walk. Harry added "he immediately said yes, of course, I'll do whatever Meghan needs," before looking ever so slightly emotional as he talked about the support the couple received from Charles.

You can try and count how many times William and Harry say they are proud of their dad in the documentary, but you'll lose track fairly quickly. From speaking about their admiration for his work setting up the Prince's Trust to their praise for how he had identified social problems that no one else was talking about, it's clear that the Duke of Cambridge and Duke of Sussex think their Dad is the bee's knees. They spoke of his "big heart" and his work ethic and made no secret of the fact that to them, Charles is the ultimate royal and the best possible father.

Prince Charles beams with happiness every time he mentions his boys, but he looked particularly touched when he found out they had actually been taking his advice to heart. "Your children always surprise you," Charles commented, "they pull your leg all the time and appear not to pay any attention at all . . . you never quite know what's happening."

But he couldn't keep the smile from his lips as he discussed how they do actually listen to him. And William and Harry put a huge amount of importance on what their dad says, showing once again just how much they really do love Charles.