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The Palace is speaking out about the topless photos of Kate Middleton that were published in French magazine Closer on Thursday.

The pictures were taken during Prince William and Kate's private holiday in France.

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A St. James's Palace spokesman tells ET in a statement, "Their Royal Highnesses have been hugely saddened to learn that a French publication and a photographer have invaded their privacy in such a grotesque and totally unjustifiable manner. The incident is reminiscent of the worst excesses of the press and paparazzi during the life of Diana, Princess of Wales, and all the more upsetting to The Duke and Duchess for being so. Their Royal Highnesses had every expectation of privacy in the remote house. It is unthinkable that anyone should take such photographs, let alone publish them."

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The Palace also just confirmed that legal proceedings for breach of privacy have been "commenced today in France" by the royal couple against the publishers of Closer Magazine France.

The Duke, 30, and Duchess of Cambridge, 30, are currently on a goodwill trip to Asia.

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"The Duke and Duchess remain focused currently on their Tour of Singapore, Malaysia, Solomon Islands and Tuvalu on behalf of HM The Queen," the statement concluded.

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UPDATE: Closer editor Laurence Pieau has spoken out in defense of publishing the revealing photos. "These photos are not in the least shocking," she told French BFM television (via AFP). "They show a young woman sunbathing topless, like the millions of women you see on beaches." Pieau even refers to the photographs as a "beautiful series," adding, "She's a real 21st century princess. ... It's a young woman who is topless, the same as you can see on any beach in France or around the world."