Revelations that Belgium's King Albert II may have a 31-year-old illegitimate daughter have created a stir - but more because of the intrusion into the royal family's life by the typically-discreet media, than the king's alleged adultery.

"This is an earthquake for the royalty. For the first time in our history, the Belgian media have looked through the keyhole of the royal palace," wrote one newspaper editor, almost apologising for the three pages of detailed articles on the allegations.

The author of the biography is an 18-year-old schoolboy

A spokeswoman for the royal palace declined to comment on what she called "malevolent gossip".

Another newspaper defended its own break with the tradition of discretion by pointing the finger at the extensive television coverage given to the story.

The paper then proceeded to reveal the address of the king's alleged illegitimate daughter, Delphine Boel, an artist living in London's Portobello Road.

It also shows pictures - also accessible on her website - of her vividly-coloured papier mache sculptures, including a cow wearing a little crown.

"Perhaps an ironic reference from the girl who could have been a princess?" the paper asks.

'No comment'

Delphine's mother, Belgian aristocrat Baroness Sybille de Selys Longchamps, who married a well-known industrialist after her birth, has refused to comment on the rumours.

Ms Boel - splashed across the front page of UK newspaper The Times on Friday - also refused to comment.

She could never succeed to the throne because the Belgian constitution states that the crown must pass to a legitimate descendant.

Story re-surfaced

The story appeared two years ago in a Belgian satirical magazine, but it has re-emerged under bizarre circumstances in a forthcoming biography of the Belgian Queen Paola.

Its author turns out to be an 18-year-old Flemish schoolboy, Mario Daneels, who calls himself a historian.

Mazarine Pingeot, right, at Francois Mitterand's funeral

Some have speculated that the rumours might have been brought to the fore by supporters of Flemish independence in order to embarrass the monarchy - a symbol of Belgian statehood - as it prepares for the long-awaited marriage of the king's heir, Prince Philippe, aged 40.

Others recall the case of Mazarine, the illegitimate daughter that the French President Francois Mitterand acknowledged as his own before he died.