Monaco's medieval royal house invited the entire population of its tiny realm to join them in celebration on Friday as the ruling Grimaldi clan prepared to embrace a glamorous new princess.

The Mediterranean tax haven declared two days of national holiday as Prince Albert II prepared to marry South African swimming champion Charlene Wittstock, hoping his romance will help him win back the hearts of his people too.

The 53-year-old playboy's lengthy bachelorhood had begun to try the patience of his people, keen for him to secure the stability and traditions of the royal house by producing a legitimate heir with his statuesque bride.

Now the Grimaldi clan hopes the wedding, and the accompanying feast days, will give their image a boost, just as the year's previous royal wedding in London gave the British monarchy a much needed shot in the arm.

"This marriage will complete the image of the principality, allow the wider public to see beyond the cliches," Monaco tourism chief Michel Bouquier told reporters. "We are going to astonish, and astonish by giving pleasure.

"Yes, Monaco is glamour, luxury, the exceptional -- it's in our DNA -- but this will help round out our image," he promised.

Certainly, no expense has been spared.

At 6:30 pm (1630 GMT), shortly after the 40 minute civil ceremony, the bells of the chapel dedicated to Monaco's patron saint Sainte Devote will ring out and champagne will be distributed in shops and businesses.

"Champagne is our national drink here," Bouquier joked.

A pink beer brewed with cranberries has been produced by Monaco's own small brewery, and will be available for two days, to complement the grilled meat on dozens of braai, the traditional barbecue of Charlene's homeland.

Bouquier said the wedding budget had been doubled to eight million euros, but the principality hopes to generate much more in tourist revenue and has laid on extra trains from France -- as many as for its annual Grand Prix.

On the eve of the ceremony, the royal couple joined a 15,000-strong crowd of their subjects and Monaco residents to cheer California rockers The Eagles at the stadium of the principality's recently relegated football team.