EXCLUSIVE: Princess Diana's Shocking Secret Will Revealed As 28th Anniversary of Tragic Royal's Car-Smash Death Looms

In a discovery fit for a royal thriller, a long-lost secret will written by Princess Diana – just weeks before her tragic 1997 death – has been uncovered – hidden inside a forgotten desk drawer in one of her favorite rooms at Kensington Palace, RadarOnline.com can reveal.

A stunned palace maid fainted on the spot when she stumbled upon the yellowed, handwritten document while cleaning out a storage room rarely used since Diana's passing. Tucked inside a jammed drawer of an antique writing desk, the princess once favored for private correspondence, the will was dated just five weeks before the fatal Paris car crash that shocked the world.

"This changes everything," a royal insider said. "We always suspected she left behind a second set of instructions, but no one could ever find them – until now."

According to palace sources, the "Second Will" was immediately reported to royal lawyers and archivists, who kept its contents under tight lock and key – until now. But RadarOnline.com has obtained exclusive details of the shocking secrets Diana left behind – stunning revelations about her sons, her ex-husband King Charles, and his then-mistress Camilla Parker Bowles that have left the monarchy reeling.

"Diana knew she was being watched," said one royal insider. "She kept this second will hidden because she didn't trust anyone around her – not the staff, not her own lawyers, and certainly not the Firm."

In the official will Diana signed in 1993, she left the bulk of her estate to Princes William and Harry, and different sums to charitable causes and her 17 godchildren.

But the newly discovered will includes other stunning last wishes and instructions.

Diana's heartbreaking message to her sons reveals a mother both loving and fearful.

"Protect each other always, no matter what they say about me, or about you," she wrote in a note attached to the new will.

She also added that no royal duty should come between their bond – and that she feared the crown "would demand more than love could withstand."

Royal sources said William was moved to tears upon reading the line: "I pray you never forget who you are, not who they want you to become. Remember, I taught you to be brave."

She also added words to her boys' future wives: "Love William and Harry until death do you part," she wrote. "I was denied that pleasure."

Diana added: "If your father takes a second wife, respect her but I pray you will always keep me safe in your heart."

Part of the will's last requests was to younger son Harry, along with this note: "I know you are a sensitive young man. I have left you a deed to land and a village of your own in a secret place in Africa. The people will welcome you with open arms and make you their king. I have included a map for you to get there. Go alone. To bring someone else invites danger."

Diana wrote to her mother-in-law: "You never understood me, no matter how desperately hard I tried. Love my sons."

She left Queen Elizabeth a key to a safety deposit box with a note saying: "For your eyes only. Please return to its rightful owner and tell her I'm so sorry."

Of course, the Queen is gone, so lawyers will have to rule on what to do with the mysterious contents of the box.

In what insiders call a "devastating swipe," Diana expressly forbade Charles from attending her funeral – a wish that, of course, was ignored after her untimely death.

"She didn't want Charles crying over her," said an insider. "He didn't."

Diana reportedly instructed that Camilla receive: "Nothing of mine … whatever is left behind in my apartments, I want disposed of upon my death so Charles' second wife cannot."

However, she did leave Camilla: "All 500 of my romance novels" with "certain notes"” she made in the margins.

She included a bottle of gin with a saucy note that said: "A toast to placing second."

Diana set aside a scholarship fund for female medical students in Lahore, the hometown of Hasnat Khan, a heart and lung surgeon who Diana had reportedly described as "Mr. Wonderful." Diana also left various amounts for other beloved charities in the same documents.

Royal experts are calling the new document "the most important royal find since the queen’s wartime letters."

And questions swirl around whether it truly disappeared or if someone in the royal family intentionally hid it. The monarchy has been thrown into a panic.

"Diana’s voice was too powerful, even in death," said one royal confidante. "Someone didn’t want her last words heard."

Now that her secret will has finally come to light, supporters are calling for a reexamination of her true wishes.

As one fan tearfully said: "She was silenced too soon. Maybe now, they can finally listen."