Kate Middleton may be mother to the future King or Queen of England, but that can’t protect her from tabloid attention, much to the frustration of the royal family.

Italian magazine Chi published two photographs of the pregnant Duchess of Cambridge in a bikini on Wednesday, inciting protest and disapproval from the palace.

Kate Middleton: Royal Pregnancy Mysteries Solved

"We are disappointed that photographs of the duke and duchess on a private holiday look likely to be published overseas. This is a clear breach of the couple's right to privacy," a spokeswoman from St. James Palace said in an official statement on Tuesday, when news of the photographs hit the Internet.

The photographs show the Duchess, with her naturally curly hair, sporting a tiny baby bump in a blue bikini, walking along the beach with William in the Caribbean island of Mustique.

In the press, pregnant celebrities often face unwelcome scrutiny over their changing bodies. But the royal baby fever is on an entirely different level. For the right to publish the first glimpse of Kate's "baby bump," publishers all over the world are paying upwards of $500,000.

Chi is the same magazine that published 18 photographs of a topless Kate Middleton in September. When French magazine Closer published the photographs, the Duke and Duchess took legal action, barring their publication.

Alfonso Signorini, the editor of Chi, balked at the palace’s suggestion that the images were an invasion of privacy. “The photographs can hardly be considered an invasion of privacy when the subjects are public figures in a public place,” he told People Magazine. “What out readers will see is simply a moment of joyful relaxation being enjoyed by a smiling, happy couple. Where’s the scandal in that?”

Women’s Day editor Fiona Connolly also ran the photographs, claiming no boundaries had been crossed. “There is no photographer hiding in the bushes and she is not inside a private villa,” she told News Ltd.

Chi Magazine cover with pregnant Kate MiddletonChi Magazine cover with pregnant Kate MiddletonFor Americans, it can be difficult to understand what the fuss is all about. But in the U.K., the press has a “gentlemen’s agreement” with the royals and with many celebrities out of respect for their privacy, Victoria Arbiter, ABC News Royal Contributor, told Yahoo! Shine. “The Palace is incensed over the publication of these photos because they're realizing that this is a battle they cannot win. The British press has been incredibly well behaved. But the idea of the whole world playing fair when there is money to be made is just ludicrous.”