A French magazine has said it will publish topless pictures of Prince William's wife Catherine on Friday, in a move met with dismay by the royal couple.
Announcing a world exclusive, Closer magazine invited readers, via its website, to pick up the new edition and enjoy "the photos that the world can't wait to see; the Duchess of Cambridge topless on a guesthouse terrace".
The pictures were apparently taken while the British royals were on holiday in France last week.
The couple are currently in Malaysia and a source travelling with them said that "their royal highnesses were saddened to learn about the alleged photos".
"The incident, if true, turns the clock back 15 years," the source said, referring to the intense media attention on William's late mother Diana, who died in a car crash while fleeing paparazzi in Paris in 1997.
The royal source added that the monarchy was investigating the authenticity of the photos and would then "make a decision about what to do".
The story was picked up in the British media on Friday, less than a month after the publication of naked pictures of William's brother Harry.
Britain's younger royals are touring the globe throughout 2012 as part of celebrations marking the 60-year reign of William's grandmother, Queen Elizabeth II.
They are now on a nine-day trip that started in Singapore. They arrived in Malaysia on Thursday, and will move on this weekend to the Solomon Islands and later Tuvalu.
Visiting a hospice in the Malaysian capital Kuala Lumpur Thursday, Kate made her first comments on foreign soil, discussing care for disease sufferers as the British monarchy continues to ease her into her official role.
On Friday, the royal couple will make a highly-anticipated public appearance at a park in central Kuala Lumpur before visiting a nature conservation site in the Borneo jungle Saturday.
But the photo row threatened to overshadow the tour, which was meant to help introduce the couple overseas after their pomp-filled marriage last year.
The April 2011 ceremony was watched by up to two billion TV viewers around the world, sparking fresh excitement in Britain's monarchy after years of crisis.
Last month a US celebrity gossip website published grainy camera-phone pictures of William's brother Harry cavorting naked with a mystery woman during a wild party in a Las Vegas hotel suite.
Harry, the third in line to the throne and a military helicopter pilot, has since been deployed to Afghanistan for a second tour of duty.