With new roles come new responsibilities. Upon ascending the throne, King Charles III officially bestowed Prince William and Duchess Kate with the royal titles of Prince of Wales and Princess of Wales, respectively — honors that the world associates with Charles and the late Princess Diana.

“It has a huge emotional weight,” royal expert Gareth Russell exclusively tells Us Weekly about the Cambridges’ new titles, specifically when it comes to the Princess of Wales moniker. “Princess Diana had such a great impact across the world with both her charisma and her fame and also her humanitarian and charitable activities.”

However, as the Do Let’s Have Another Drink!: The Dry Wit and Fizzy Life of Queen Elizabeth the Queen Mother author explains, “But the title [of Princess of Wales], you know, was used by many people before Diana, and … it is now being used afterward.”

Russell believes that William and Kate — as well as the public — will honor Diana’s legacy with “a real respect” with their new titles, he tells Us. The couple, who are parents of Prince George, 9, Princess Charlotte, 7, and Prince Louis, 4, have frequently honored William’s late mother, who was killed in a car crash in August 1997.

“I think it is quite moving for a lot of people that the last person to hold [the Princess of Wales title] was William’s mother and now it’s his wife,” the royal historian elaborates. “I think it puts a good kind of pressure [on the Cambridges] because it brings a lot of the … emotional collateral charisma that Princess Diana had … and invests that title with a certain emotional appeal to people.”

In his inaugural address as king on Friday, September 9 — one day after Queen Elizabeth II died at age 96 at her Balmoral estate in Scotland — Charles, 73, declared his allegiance to the crown.

“I … solemnly pledge myself throughout the remaining time God grants me to uphold the constitutional principles at the heart of our nation. … I shall endeavor to serve you with loyalty, respect, and love as I have throughout my life,” the new monarch stated in the video address. “My life will, of course, change as I take up my new responsibilities. It will no longer be possible for me to give so much of my time and energies to the charities and issues for which I care so deeply. But I know this important work will go on in the trusted hands of others.”

Those “trusted hands” include William and Kate, upon whom Charles also granted Duke and Duchess of Cornwall, respectively.

“With Catherine beside him, our new prince and princess of Wales will, I know, continue to inspire and lead our national conversations, helping to bring the marginal to the center ground where vital help can be given,” the sovereign stated.

As for Russell’s take on the king’s future, “I think the speech today gave us is our best indicator that he absolutely is ready to be king,” the expert notes.