Princess Charlotte Kept Brother Prince George 'in Line' During Queen Elizabeth's Funeral (Exclusive)

ET spoke with Norah O'Donnell and Gayle King about their observations from the queen's funeral.

It was a solemn day for the eldest children of Prince William and Kate MiddletonPrince George, 9, and Princess Charlotte, 7, who paid tribute to their great-grandmother, Queen Elizabeth II, alongside their parents during her funeral at Westminster Abbey on Monday.

Charlotte was seen wearing a horseshoe brooch in a touching tribute to her late great-grandmother, who loved horses. A source tells ET that the brooch was a gift from the queen. George was dressed in a navy blue suit as he joined his sister and other members of the royal family. Missing from the occasion was William and Kate's youngest son, 4-year-old Prince Louis. 

ET's Kevin Frazier spoke with Gayle King, who revealed that she was told the royal duo wanted to be part of the day's ceremonies, despite the heaviness of the day. 

"I'm told that there was a conversation with [their] mom and dad about [whether] they [were] up for it," she shared, adding that William and Kate "put it out" to the children to make their own decision. "We just learned about the decision this morning that they were gonna participate."

King said that from her perspective, the pair's presence seemed to be "setting a scene." 

"The queen [was] never expected to be queen, she became second in line for the throne when she was just 10... she never thought she would actually be queen, she thought her father would serve out. Prince George is nine and he now is in line for the throne. I think that's an interesting thing," she noted. 

Upon Queen Elizabeth II's death at the age of 96 on Sept. 8, George, Charlotte, and Louis, became second, third, and fourth in line to the royal throne, respectively. Their parents have become the new Prince and Princess of Wales, titles previously held by the new King Charles III, and the late Princess Diana

"Certainly, [George] is being prepared -- just the fact that he is being subjected to all these formal events and I think his parents are starting early to let him know, 'You will have a very different life,'" King added. "They want [George, Charlotte and Louis] to have as normal a life as possible, they've made that very clear. That's one of the reasons why they moved to Windsor and why they're gonna go to school. It's a little out of the public eye but his life is forever changed. Prince Charles is now King Charles, Prince William is now the heir to the throne and now Prince George's life is changed. But they are up for it."

Royal expert Katie Nicholl echoed the sentiment, noting that having George and Charlotte at the ceremony "very young" was sending a "clear message."

"This is the future, this is the future of the dynasty. This is a projection of what's to come. George is now second in line for the throne and I think the significance of having Charlotte was 'and this is the spare,'" Nicholl observed. "We've always had an heir and a spare, it dates back centuries ago... You look back and you see the queen was supported by Princess Margaret, her sister, Charles was supported by [Anne, Princess Royal] and William was supported up until recently by Harry. That notion of the heir and the spare is continued by George and Charlotte and it's lovely."

Norah O'Donnell, anchor and managing editor at CBS Evening News, agreed with that line of thought, noting that George handled the emotional day "like the second in line" with Charlotte supporting him.

When the two stood with their parents waiting for Queen Elizabeth's coffin to go past them at Wellington Arch, Charlotte can be seen telling her older brother, "You need to bow." George listens intently as she gives the instruction, later looking to her for his cue and bowing his head promptly. 

"We all wish our children were as well-behaved as Prince George and Princess Charlotte," O'Donnell said, laughing. "It was once again like she was keeping her older brother in line. When you talk to royal experts... it's about showing the continuity of the monarchy. That's why I think they wanted the children there, to show continuity. This has lasted a thousand years and it's going to continue to last."

For more on Her Majesty's death, and Queen Elizabeth II's funeralcheck out ET's ongoing coverage.