Queen Elizabeth is well aware of the pressure that comes along with being an heir to the British. When Prince William was young, the monarch feared the powerful position would overwhelm her grandson, and he would end up cracking like his mother, Princess Diana.

Although Elizabeth spends a majority of her time handling her royal duties, the monarch reportedly experienced a moment of sadness when she realized her responsibilities kept her from bonding with William.

In the book, “My Husband and I: The Inside Story of 70 Years of the Royal Marriage,” Ingrid Seward claimed, Queen Elizabeth began to strengthen her bond with Prince William after Princess Diana’s exposed details about Prince Charles’s affair in her Panorama interview.

The author claimed Elizabeth felt obligated to mentor the future king. “The one person who could help, who had to help, was the Queen. She knew only too well what pressures William was facing. She told her advisors she feared he might crack up like his mother had,” Seward wrote.

“He started joining the Queen and the Duke of Edinburgh for lunch. Afterwards, Prince Philip would leave the Queen and her grandson together in the Oak Drawing Room overlooking the quadrangle.”

Queen Elizabeth and Prince William’s private sessions allowed them to form a special bond with one another. “They talked in a way they never could have done before. One of her great sadnesses was that, until the separation, she had hardly seen him.” Seward explained.

“Now, at last, she was able to do so on a regular basis and form a proper relationship. In this quiet intimacy, the Queen was able to impress upon William that the institution of the monarchy was something to be upheld and respected, and worth preserving.”

Since Prince William is second in line to the British throne, the heir continues to receive advice and lessons for his future role as king. Years after his specials sessions with Queen Elizabeth, the royals’ continue to have a close bond, as he prepares for the day when he ascends the throne.

Queen Elizabeth and Prince William
Queen Elizabeth II worried about Prince William. The Duke of Cambridge is pictured during “The Patron’s Lunch” celebrations for The Queen’s 90th birthday on June 12, 2016 in London, England. Jeff Spicer/Getty Images