Under the headline "Oh My God!," the magazine, Closer, gave a preview of the cover on its website featuring pixilated photos of the Duchess of Cambridge, 30, in a bikini and about to remove her top.
PHOTOS: The Life and Times of Kate Middleton
The pictures were reportedly taken while Middleton and Prince William, who celebrated their one-year wedding anniversary in April, enjoyed a mini four-day vacation together last week at a secluded chateau in the south of France before beginning a tour of the Far East and South Pacific to celebrate Queen Elizabeth II's Diamond Jubilee.
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The royal couple was reportedly told about the photos as they ate breakfast Friday before visiting a mosque in Malaysia. A palace source tells ABC News that at first the couple simply felt saddened, but as the day wore on the sadness turned to shock and anger.
The St. James Palace released a statement Friday, calling the invasion of the young royal's privacy "grotesque and totally unjustifiable."
"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," read the statement.
The revelation came just one day after Middleton marked an important first as a royal, delivering her first official speech overseas. The well-received speech was delivered to staff and patients at the Hospis Malaysia in Kuala Lumpur and focused on the importance of specialized medical care for seriously ill children. Middleton is a Royal Patron of East Anglia's Children's Hospices in England.
READ MORE: Kate Middleton Marks a First as a Royal
The couple, who also visited Singapore and will end their trip this weekend in the island nation of Tuvalu, has been met by cheering crowds at each spot so far on their tour. Thursday's event at the hospice was no different, with a barrier collapsing from the weight of fans reaching out to see them. Young children from a nearby school greeted Kate and William, who joined her for the visit, outside the hospice with Malaysian flags and a welcome banner. Once inside, the couple met with young patients and drew with them on clay bricks, according to reports.
Despite the topless photo revelation, today the royal couple carried on in public as if nothing had happened. At the visit to the mosque, Middleton politely removed her heels and wore a stylish scarf in accordance with Muslim tradition.
Just after William and Middleton were engaged, the prince expressed his concerns about the paparazzi and said he had given Middleton the chance to get out of the relationship if she thought the attention would overwhelm her.
"I wanted to give her a chance to see in and to back out if she needed to before it all got too much. I'm trying to learn from lessons done in the past and I just wanted to give her the best chance to settle in and to see what happens on the other side," the prince said.
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Middleton is consulting lawyers to consider what options may be available, according to the statement issued by the palace.
Last month, nude photographs of Prince William's younger brother, Prince Harry, partying in a Las Vegas hotel surfaced online and made headlines around the world. In that case, the palace contacted the Press Complaints Commission, which advised British newspapers to not publish the pictures.
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