More than 200 pictures of the Duchess of Cambridge naked are reported to exist, according to the editor of Chi.
The Italian gossip magazine is planning to publish 50 of the pictures in a 26-page special edition due to hit the newsstands on Monday.
The pictures first came to light on Friday when the French edition of Closer magazine published several shots of the future queen topless.
Topless pictures of the Duchess first appeared on Friday
Lawyers for the Royal family will go to court on Monday seeking damages and an injunction against further publication of topless photographs of the Duchess, a St James's Palace spokesman said.
The legal action aims to prevent further publication against French Closer magazine's parent company.
Closer is published by the Mondadori media group which also publishes Italian gossip magazine Chi - which has promised a 26-page special edition featuring images of the royal couple on holiday, but the palace said no decision has been taken on separate legal proceedings in Italy.
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The case will begin in Paris in the afternoon and is expected to be held in public.
The palace spokesman said: "The court hearing is in France tomorrow when the official proceedings will start at a court in Paris as the papers have been served.
"It is the first airing and we will be seeking an injunction from them using the pictures and it will lead to a longer court case where damages will be sought."
The Palace could also pursue an action in Ireland against the Irish Daily Star, which has also published some of the pictures. Following its actions, the newspaper could face closure after Richard Desmond, the co-owner, moved to end the Anglo-Irish joint venture between Northern & Shell and INM.
Despite the possibility of legal action, Chi, which is owned by Silvio Berlusconi's Mondadori Media, looks set to push ahead with publication of the pictures, with the editor, Alfonso Signori, arguing that legal action was unlikely as the Duchess was in a public place when the pictures were taken.
Berlusconi's Mondadori Media owns both Chi and the French edition of Closer
In an online message regarding the pictures, Signori echoed the sentiments of Closer editor Laurence Pieau, also owned by Mondadori. He said: "The fact that these are the future rulers of England makes the article more interesting and topical.
"This is a deserving topic because it shows in a completely natural way the daily life of a very famous, young and modern couple in love."
He added: "These pictures were taken while the couple were on a terrace and they were taken from a public place so there is no suggestion of an invasion of privacy."
On Sunday, Signori mischievously tweeted: "Happy Sunday to all. And to Her Majesty the Queen."
The cover of the magazine, which will feature three shots of the Duchess topless, has already been widely circulated in the Italian media, and will run with the headline: "Court Scandal: The Queen is Nude!"
In 2007, the magazine courted similar controversy printing pictures of Princess Diana as she lay dying in the back of the car following the Paris crash that killed her and Dodi Fayed.
In 2007 Chi printed pictures of Diana's final moments
Away from the growing media storm, Kate and Wills put on a brave face on the latest leg of their tour of Southeast Asia, receiving a rapturous welcome from the people of the Solomon Islands on Sunday, who came out in their tens of thousands to cheer their future King and Queen.
Riding in a symbolic war canoe along palm-tree lined roads and with a garland of flowers around their necks the Duke and Duchess appeared a world away from the furore that surrounds the publication of the Duchess's topless photos.
From an open-topped Toyota van decorated to look like a fearsome war vessel they waved and smiled back at the crowds who stood five deep in places.
The Duke and Duchess with His Excellency the Governor General of the Solomon Islands
Kate steps out in traditional Island clothing
Kate looking tanned in pink
The screaming well-wishers lined the royal couple's five-mile route from the airport into Honiara - capital of the South Pacific nation - and a police car with lights flashing and its siren blazing led the way to clear the crowds.
Barbara Daufanamae, 21, a student and friend Frances Vahimana, 22, both from Honiara, had waited for hours in sweltering temperatures to see the royals who are touring the region in celebration of the Queen's Diamond Jubilee, and when they passed were left shaking with excitement.
Daufanamae summed up the mood when she said: "We are just so excited to see them come here. I think almost everyone in Honiara is here.
"This is just so unexpected, it's such a privilege for the country, out of all the countries of the Pacific to have them come here is a privilege.
"Nothing really happens in town so when some body comes everybody comes out and everybody goes crazy."
William and Kate tour of the Far East and South Pacific - Day Six
Kate And Prince William Tour - Day 5
