Royal expert Rebecca Long told Us Weekly Wednesday the 37-year-old’s first-ever solo outing with Queen Elizabeth II at King’s College London in mid-March was designed to prepare the Duchess of Cambridge’s most important role.
Middleton became a member of the British royal family when she married Prince William in 2011. William, 36, is the queen’s grandson and second in line to the throne.
The couple share three children: Princes George and Louis, as well as Princess Charlotte.
“Kate’s been taking on new responsibilities little by little over the last few years, so it won’t be a shock when the time comes,” Long explained. “William and Kate are the favorite royals to take the crown in many generations, so the people of the U.K. are very excited about it.”
Elizabeth, 92, is also determined to show Middleton how to settle into her future title gracefully in the public eye.
“She’s really taken Kate under her wing,” a source close to the royal family told Us Weekly. “The two of them will often spend hours discussing royal life and the future of the monarchy.”
“It’s taken a long time for Kate to get to where she is today,” added a second insider. “But she’s ready.”
Earlier this month, royal expert Katie Nicholl told Glamour magazine that rumors of an alleged feud between Middleton and Markle are greatly exaggerated, but that doesn’t mean the sisters-in-law are necessarily eager to hang out together.
"I think this idea of there being a catfight between the two duchesses has made tantalizing headlines, but I don't believe that," royal expert Katie Nicholl told Glamour. "I've never heard from my sources that there has ever been a feud or a falling out."
However, Nicholl says there is one rumored incident between the royal wives that she does think holds some water.
"I had heard about an upset over the dress fitting for Princess Charlotte," Nicholl said, referring to Markle allegedly making Middleton cry ahead of Prince Harry's royal wedding. "And I had heard that while Harry was very keen for the two of them to become best friends, there was never that sort of a friendship."
"I know in the early days Kate invited Meghan over to apartment 1A for tea. Obviously, she took her on that high-profile trip to Wimbledon, so they have spent time together. But what I think hasn't happened is — they haven't become best friends out of all of it," Nicholl said. "That's not to say they hate each other. I don't believe that to be the case at all."
"They quite quickly realized they were two pretty mature women – quite different women – and really the only thing they had in common was they'd married princes," Nicholl explained. "Not just Prince Harry, I think probably the world wanted them to become best friends."
However, Nicholl does believe that Prince Harry and Prince William may not have seen eye to eye recently. Reports suggested that William warned Harry not to rush into marriage with Markle, while allegedly "riled" the Ginger Prince.
"I do think there is some truth to there having been some tension — not just between the duchesses but between the dukes, as well," Nicholl said. "As we all know, things can gather momentum pretty quickly. So while I think there's been tension, I don't believe there has been some feud."
As for Markle and Middleton's recent highly publicized hug, Nicholl says that was a strategic move.
"I do know that Meghan and Kate have come to an agreement to get along, to make an effort, to be amiable and warm toward each other in public," she said. "They both realize it's in neither of their interests to have these catfight headlines. It's not what either of them wants."
Fox News’ Jessica Sager contributed to this report.