Prince William 'Totally Cut Out' Prince Harry Amid Princess Diana BBC Drama

The battle of the brothers continues. Prince William's very rare statement about his mother, Princess Diana, has stunned Prince Harry, who received no heads up that it was going to be issued without him.

"Harry has stepped down from his senior role in the Royal family, but didn't expect to be totally cut out, especially when it came to the mother they shared together, Princess Diana," a source exclusively tells OK!. "In the past, any official statement regarding their mom would have been a joint statement. The brothers disagree on many things, but when it comes to protecting their late mother and her legacy, they were always united."

William has spoken out about the BBC controversy surrounding Diana's 1995 interview with Martin Bashir on his show, Panorama. It has been alleged that Bashir used fake bank account documents to convince the Princess to do the interview.

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In a statement released by Kensington Palace, William said: "The independent investigation is a step in the right direction. It should help establish the truth behind the actions that led to the Panorama interview and subsequent decisions taken by those in the BBC at the time."

"William's decision to move forward without consulting or even telling Harry is huge. He is moving on without him. Harry can't have it both way. Harry decided to leave, he wasn't pushed out, and now it is life as usual without him," adds an insider. "If Harry wants to issue his own statement about the BBC investigation, that is up to him."

Lord Dyson — the former president of the Court of Appeal of England — will lead the independent investigation, which will begin immediately. The respected judge will interview several witnesses linked to the program in order to find out how the corporation landed the scoop. Dyson will also focus on what really happened between Bashir and the Princess of Wales leading up to the bombshell interview that shocked the world.

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During Bashir's conversation with Diana — who was killed in a car crash at age 36 — famously said: "Well, there were three of us in this marriage, so it was a bit crowded." Diana was married to Prince Charles, who was infamously having an affair with Camilla Parker Bowles — his now wife.

Harry, 36, and his wife, Meghan Markle, stepped away from their royal duties in March to "rebrand themselves" as Hollywood stars in Montecito, Calif. While the brothers have had tension for years, Harry stepping away from his senior royal duties was the last straw for his older brother.

William, 38 — who felt "blindsided" and "incredibly hurt" after finding out Harry and the Suits alum were going through with their departure — isn't planning on reconciling with Harry anytime soon. "I put my arm around my brother all our lives," the older brother said, according to the new book, Battle of Brothers: William & Harry — The Inside Story of a Family in Tumult. "I can’t do it anymore. We're separate entities."

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Despite their never-ending feud, William and Harry both felt a great loss when their mother was tragically killed and continue to suffer years later. "I think being part of this family, in this role, in this job, every single time I see a camera, every single time I hear a click, every single time I see a flash, it takes me straight back," the Duke of Sussex previously said in the BBC One documentary Football, Prince William and Our Mental Health. "So, in that respect, it's the worst reminder of her life, as opposed to the best."

The Duke of Cambridge — who shares three children with wife Kate Middleton — explained, "When you've been through something traumatic in life, that is, your dad not being around, my mother dying when I was younger, your emotions come back in leaps and bounds because it's a very different phase of life, and there's no one there to kind of help you."