It is said that there is no getting back the closeness that Prince William once shared with his younger brother Prince Harry. Their relationship has reportedly reached rock bottom and there is no moving back, only forward.

The Duke of Cambridge is believed to be "mourning" the collapse of his relationship with his sibling. According to OK! magazine, he feels sad that he has lost the only person, aside from Kate Middleton, who shared the same sentiments when it came to their royal life.

"He truly loves Harry and feels he has lost the only person, aside from his wife, who understood this strange life of theirs," a source said adding, "But he believes there are things you just don't do. And Harry has 100 percent crossed that line."

Prince William reportedly believes that Prince Harry has "disrespected" Queen Elizabeth II and the royal family. Meanwhile, another insider claimed that the Duke of Sussex's relationship with his brother is at "rock bottom."

The 39-year-old is believed to be "deeply upset" about his feud with his brother. He feels "let down" but he has learned to "move on."

The royals recently gathered for the Platinum Jubilee celebrations. The Duke and Duchess of Sussex made the trip to the U.K. but only attended one public engagement: the Thanksgiving Service at St. Paul's Cathedral. They were not seen publicly mingling with the senior royals including Prince William and Kate Middleton, and Prince Charles and Camilla.

It is understood that palace aides made certain that Prince Harry and Meghan Markle were not seen together with the Duke and Duchess of Cambridge. This was to prevent any royal drama and avoid catering to the public's interest in seeing the brothers talking to each other.

The last time the siblings were seen in public together was during the unveiling of Princess Diana's statue at Kensington Palace in July 2021. They also chatted after Prince Philip's funeral in April.

In an interview in 2019, Prince Harry admitted that he and Prince William had gone on different paths. Contrary to popular belief, royal author Tina Brown claimed Meghan Markle is not to blame for the brothers' feud. She said it started when the Duke of Sussex left the military in 2015. He met the duchess on a blind date in 2017.

Prince William and Prince Harry
Prince William and Prince Harry's relationship -- once close -- has soured Gareth Fuller/POOL