Prince William Struggled With Prince Harry's Departure, Thought Brother Would Support Him: Royal Biographer

Prince William and Kate Middleton had to take more workload after Prince Harry and Meghan Markle stepped back from their royal duties, according to a royal biographer.

The Duke and Duchess of Sussex's decision to leave the firm directly affected the Duke and Duchess of Cambridge. Vanity Fair royal editor Katie Nicholl, the author of "The New Royals," said Prince Harry's departure contributed to his older brother's struggles.

"The impact of Harry leaving [is] possibly one of the reasons why William has struggled so much with this," Nicholl told Fox News Digital. "Of course, it did have an immediate impact on William, his wife, Kate, and their young children. There was an increased workload almost overnight, which as a couple, they were very happy to undertake."

Aside from the additional workload, Nicholl added that the Sussexes' exit also "shifted the spotlight" on the Cambridges and their young family, which "wouldn't necessarily have happened so soon." She added that the Prince of Wales always thought his sibling would be there to support him.

"I think William always believed that Harry was going to be his wingman. He always believed that was the plan from day one ... Harry would be there to support him," the "Harry: Life, Loss, and Love" author said.

In an interview on GB News' "Dan Wootton Tonight," Nicholl discussed the royal brothers' relationship. She claimed that Prince William "simply can't forgive" Prince Harry for abandoning his duties.

"He always thought Harry would be his wingman, now he's doing it on his own. Thank goodness he's got Kate by his side," she told host Dan Wootton.

The late Queen Elizabeth reportedly wanted her grandchildren to reconcile. She was also "very hurt" by the "turmoil" of Prince Harry and Meghan Markle's decision. However, she realized there was only so much she could do.

"I think [the Queen] realized that there was nothing more that she could do to forge a reconciliation between William and Harry," Nicholl suggested on the show on Thursday. "I think most people think it is terribly sad that the twilight years of her reign when she should have been enjoying her time, spending her time with her great-grandchildren and grandchildren, was marred by this awful family rift."

Nicholl's new book, "The New Royals," came out Tuesday.