The royal family embarked on a legal battle Monday to try to stop the spread of topless photos of Prince William's wife Catherine, as an Italian magazine splashed the pictures across a special 38-page edition.

"The queen is nude!" read the front-page headline of Chi magazine which reproduced the photos first published last week by the French publication Closer. Like Chi, Closer is owned by Italian former prime minister Silvio Berlusconi.

It is Closer that William, the second-in-line to the throne, and his wife are targeting at a court in the Paris suburb Nanterre where they were due on Monday to seek an injunction to stop the magazine re-selling the images.

The couple are also lodging a criminal complaint with French prosecutors seeking damages from the the gossip magazine and from the photographer who took the photos with a powerful telephoto lens as the couple holidayed in southern France.

Lawyers for the Duke and Duchess of Cambridge argue that publishing the photos of Catherine sunbathing semi-naked at a chateau, and of William rubbing suncream on her behind, breached their privacy.

The prince is furious over the images, which drew comparisons with press harassment of his mother Diana who died in a Paris car crash in 1997 while pursued by paparazzi.

No newspaper or magazine in Britain -- whose racy, mass-selling tabloids have frequently been accused of unwarranted intrusion into the lives of the rich and famous -- has announced plans to publish the offending photographs.

But the possibility of legal action failed to intimidate Irish or Italian titles, with the pics of Catherine sunning herself in bikini briefs appearing Saturday in a Dublin tabloid and Chi magazine publishing them on Monday.

Chi produced a special edition featuring the grainy photos along with a series of articles on topics such as "Kate's breasts, natural or fake?"

The Mondadori group which owns the magazine is chaired by Berlusconi's daughter Marina Berlusconi, who on Sunday defended running the pictures as a matter of editorial freedom.

The magazine's editor Alfonso Signorini argued in the special edition that the pictures represented "extraordinary reportage."

"For the first time, the future queen of England was appearing in a natural way, without the constraints of etiquette," he wrote.

In 2006, Chi sparked outrage in Britain when it printed a photo of a fatally injured Princess Diana being given oxygen at the scene of the high-speed crash in a Paris road tunnel in 1997, together with details from her autopsy.

A royal spokeswoman declined to comment Sunday on whether the royal family was launching legal action against either Chi or the Irish Daily Star.

"All proportionate responses will be kept under review," she said.

Unlike Mondadori, the two media groups that jointly own the Irish Daily Star condemned its decision to run the pictures.

Britain's Northern and Shell group said it was taking "immediate steps" to shut down the joint venture with Dublin-based publisher Independent News and Media which runs the Irish Daily Star.

Last month photos emerged of William's brother Prince Harry cavorting naked with women at a Las Vegas party.

The two images of Harry are widely available on the Internet but in Britain only The Sun newspaper published them.

The palace has said the couple, marking Queen Elizabeth's 60 years on the throne.

[Image via Agence France-Presse]