Prince Albert of Monaco has been forced to issue a public statement after claims his fiancée tried to flee to South Africa after learning of his third illegitimate child.
The royal family dismissed reports Charlene Wittstock - a former Olympic swimmer -- tried to return to her homeland.
The claims seem to have originated from the French news magazine L'Express.
In an article headlined 'Albert-Charlene: Marriage in Peril' and published on its website, the magazine claimed Miss Wittstock had been upset to hear a new revelation about her future husband.
A lawyer for Prince Albert vigorously denied the claims, described the story as 'madness', adding: 'Everything is false'.
The allegations emerged just two days before the three-day celebrations for the £50 million wedding are to start.
The event is the biggest thing to hit Monaco since Grace Kelly married Prince Rainier III in 1956.
The guest list reads like a who's who of the rich and famous, and includes Naomi Campbell, Topshop boss Philip Green, Richard Branson, and Giorgio Armani.
Dozens of royal guests will also attend, including the Earl and Countess of Wessex.
'These rumours, spread a few days before the wedding ceremonies of His Serene Highness Prince Albert and Miss Charlene Wittstock, have only one purpose - to seriously damage the Sovereign's image and by consequence that of Miss Wittstock and to cause serious prejudice to a happy event.'
Prince Albert's lawyer, Thierry Lacoste, confirmed he would be taking legal action against the French publication and added: 'I was with the Prince and Charlene Wittstock in Paris three days ago, and I can promise you that all is well.'