According to a new biography about Carolyn Bessette-Kennedy, John F. Kennedy Jr.’s wife suggested that he call Prince William and Prince Harry following the tragic death of their mother Princess Diana in 1997.

In Once Upon a Time: The Captivating Life of Carolyn Bessette-Kennedy, which was excerpted in PEOPLE on May 16, author Elizabeth Beller wrote, “Carolyn tried to get John to call Princes William and Harry to give his condolences when it came out that Diana had hoped for her sons to emulate John’s modesty in the face of media obsession.”

However, John is said to have been reluctant “as he didn’t know them and thought that their situations greatly differed.”

©Justin Ide/Newsmakers

Per Elizabeth, John had met Princess Diana “once or twice,” and “the fact that she had died while being chased down by paparazzi, he was aware of the fact that their [he and Carolyn’s] lives were becoming overwrought with attention and he was upset.”

The author added, “Carolyn’s suggestion was lovely that he call them. He was, by all accounts, a lovely, gracious person, but maybe that moment was too difficult for him to be able to reach out and say something to someone who’s just lost their parent in a very public and dramatic way.”

William and Harry were just 15 and 12 years old, respectively, when their mother died. Like the Princes, John also lost a parent at a young age. He was nearly three years old when his father President John F. Kennedy was assassinated in 1963. JFK Jr. turned three on the day of his dad’s funeral. Decades later in 1999, John and his wife Carolyn, whom he wed in 1996, died in a tragic plane crash.