Princess Diana's biographer says Kate Middleton wasn't prepared for royal life, just like Meghan Markle

• Kate Middleton reportedly wasn't prepared for royal life when she married Prince William in 2011.
• Royal biographer Andrew Morton says Middleton faced similar struggles to Meghan Markle.
• He said it took Middleton a long time to be "in control and in command of what she's doing."

Princess Diana's biographer Andrew Morton said Meghan Markle wasn't the only royal woman who entered the family unprepared.

Morton is best known for the biography, "Diana: Her True Story," for which the late princess provided secretly recorded tapes for the author to use as material for the book, published in 1992.

Speaking on the Royally Obsessed podcast last week, Morton said Markle's claims that she wasn't offered formal training when she entered the royal family wasn't surprising.

The duchess of Sussex told Oprah Winfrey that royal training "might exist for other members of the family," but "that was not something that was offered to me."

Markle said she took it upon herself to learn the British national anthem and hymns sung in church services.

"During the interview, she said, 'Nobody told me about the national anthem.' Quite frankly, they don't tell you," Morton said. "It's not like there's a school for princesses where you sit there and go through the procedures from A to Z. You learn it at the knee. You learn it from experience."

"Even Catherine Middleton, the point I'd make about her is that yes, she had the support of her family, and yes, she was British and knew what was expected, but nobody can prepare you for the level of intensity and the level of interest in you," Morton said.

Morton added that it has taken the duchess of Cambridge "quite a long time" to be "in control and in command of what she's doing."

"Even Diana, it took her years, and she was an aristocrat," he said.

It's been almost 10 years since Middleton married into the royal family on April 29, 2011.

The duchess of Cambridge was subjected to negative press in the lead-up to her wedding. She was given the nicknames "Lazy Katie" and "Waity Katie" in reference to reports that she quit her job before marrying Prince William.

"Obviously Catherine was slagged off before the marriage, but now that she does everything right, allegedly, the press coverage has changed," royal expert Marlene Koenig previously told Insider.

Koenig compared Middleton to the late Princess Grace of Monaco, the American actress Grace Kelly, whom she says "took a long time to be accepted" in the country.

Morton also criticized Markle's suggestions that she had no freedom at Kensington Palace.

The duchess told Oprah that her passport, driver's license, and keys were taken away from her when she joined the royal family.

"She didn't have any keys, she didn't have a car, she didn't have a place to live," Morton said on the podcast.

"She was able to go to New York on a private jet to celebrate a baby shower and make eight overseas trips without wearing handcuffs," he added.

The duchess of Sussex traveled to New York in February 2019 for her baby shower, which was reportedly hosted by her friends Serena Williams and Amal Clooney.

Markle, Prince Harry, and their son, Archie reportedly flew by private jet to a holiday resort in Ibiza in August 2019, before traveling to Elton John's home in the south of France shortly after.

The couple also made various overseas trips on behalf of the queen, including a royal tour of Australia, New Zealand, and Fiji, a tour of Morocco, and a tour of southern Africa.

Representatives for the duchess of Sussex did not immediately respond to Insider's request for comment.