While Prince William and Prince Harry played nice for the cameras while attending Prince Philip's funeral on April 17, royal expert Robert Lacey claimed that behind closed doors, the two were still hostile towards each other.
"There they were, at each other's throats as fiercely as ever," one friend told Lacey. "The rage and anger between those two has grown so incredibly deep. Too many harsh and wounding things have been said."
The historian also stated that despite reports, the royals didn't hold a "mini summit" after the funeral. Instead, William left with Kate Middleton and returned home to their three kids.
"The conflict between Diana's two bitterly divided sons does not seem likely to end any time soon," Lacey shared.
However, there could be "happier tidings" ahead. "The oh-so-unforgiving and unforgetting brothers are surrounded by a network of devoted friends and a few family members who are working seriously to ease the path to a truce," the expert revealed.
The siblings will come face-to-face again on July 1, when a statue of their late mother Princess Diana will debut.
The guest list for the event had to be dramatically cut down, so even William's wife is expected to sit out, as is Meghan Markle, who's staying in California to look after 2-year-old son Archie and newborn daughter Lilibet.
"Prince William and Prince Harry will attend a small event to mark the unveiling of a statue they commissioned of their mother, Diana, Princess of Wales, in the Sunken Garden at Kensington Palace on Thursday 1st July," a message from Kensington Palace read. "In addition to close family of Diana, Princess of Wales, members of the statue committee, the sculptor Ian Rank-Broadley, and garden designer, Pip Morrison, will also be present. Further details about the statue and garden will be provided on the 1st July."