Though Prince William and Prince Harry have drifted apart over the past few years, author Robert Lacey recalled a simpler time between the siblings in his book Battle of Brothers.
Excerpted by The Sun, the royal expert's work offers some insight into the early years of their relationship, revealing that when Princess Diana and Prince Charles introduced the Duke of Cambridge to his baby brother, he "rushed forward at once to plant a kiss on the baby’s forehead, then sat on the bed and held the newborn warmly in his arms."
"When the family went back to Kensington Palace, it was William who led the way in the presentation of the baby to the staff below stairs, smothering his little brother in kisses," the book reads. "Though he did also attempt the odd headbutt on the new arrival."
Lacey continued, "For years the world would be struck by the fondly possessive way in which young William liked to display his younger brother and show him off proudly – almost as his favourite toy."
While the brothers remained thick as thieves for years, Harry's romance with Meghan Markle began to take a toll on the siblings' bond.
In Andrew Morton's updated work Meghan and the Unmasking of the Monarch, he explained that William's lack of support disappointed the Duke of Sussex.
"I think that Harry resented the fact that he supported his relationship with Kate Middleton over the years," the writer explained to Fox News. "We forget that the palace didn’t believe she and William would marry. They didn’t think she had what it took to be the future queen, initially. But Harry always supported her. He was always friendly with Catherine. They were always joking and laughing together."
"The fact that William couldn’t do the same for him did not sit well with Harry," Morton continued. "There’s no doubt that there was a divide between the brothers."
Harry said as much in his interview with Oprah Winfrey, revealing the two had a falling out when he decided to leave the royal family.
"I love William to bits. He's my brother," the father-of-two insisted. "We've been through hell together. But we are on different paths."
Since then, the duo have reunited at Prince Philip's funeral and a July ceremony that honored their mother, but last month, Finding Freedom author Omid Scobie told Entertainment Tonight, "the relationship between Harry and William is still very much one of distance. I don't just mean physical [distance], across the Atlantic, but they are not talking that much, and that is exactly how sources close to William have put it."