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A letter written by Diana, Princess Of Wales three weeks before her death sold for $3,840 at an auction on April 14.

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Her last official note, penned on Kensington Palace-headed paper, was to landmine campaigner Dilys Cheetham, thanking her for her work for the cause.

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She also told Cheetham she was "deeply moved" by a recent trip to Bosnia and pledged to continue supporting anti-landmine charities.

It was dated just three weeks before the princess died in a car crash in Paris, France on Aug. 31, 1997.

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The letter was bought by a private buyer for $3,840 at Fellows Auctioneers in Birmingham, England.