Venice (dpa) - US billionaire Jeff Bezos and former TV presenter Lauren Sánchez headed to San Giorgio island in the Venice lagoon late on Friday, where the two are to exchange vows before a star-studded cast of 200 guests.

The exclusive - and presumably exorbitantly expensive - party is to continue until Sunday.

Guests at the event, dubbed the wedding of the year, include Kim Kardashian, Bill Gates, Leonardo DiCaprio and Orlando Bloom.

The British tabloid Daily Mail has reported that Bezos and Sánchez secretly married in the United States a few weeks ago. Nobody in the couple's entourage responded to dpa's request for comment.

The 61-year-old Amazon founder - one of the world's richest men with an estimated fortune of $220 billion - and 55-year-old Sánchez are both marrying for the second time. They have seven children combined from previous relationships.

Which dress to choose?

On Thursday evening, a party was held in the former monastery church Madonna dell'Orto. Following Friday's ceremony, a huge fireworks display is planned for all to see.

According to media reports, Sánchez has 27 dresses ready for the wedding weekend.

For the ceremony, she was hesitating between a dress by Dolce&Gabbana and one by Oscar de la Renta, according to Italian daily La Repubblica. Bezos is said to have opted for a tuxedo by Giorgio Armani.

Heightened security

The celebrations are taking place under strict security measures and great secrecy due to concerns about protests or an attack. Police and military are present throughout the northern Italian city, which is hosting more than 100,000 tourists daily.

Bezos and Sánchez are staying in a luxury hotel on the Grand Canal, with the wedding party spread across several others. Guests include the US president's daughter Ivanka Trump and TV presenter Oprah Winfrey.

According to media reports, Barbra Streisand, Mick Jagger and Elton John are also on the guest list. At the ceremony, Matteo Bocelli, the son of star tenor Andrea Bocelli, is expected to sing. His father is unavailable.

Wedding banquet: Pizza and pasta

The northern Italian celebration will feature a taste of southern Italy, with pizza, pasta and lemon dessert on the menu, according to the Corriere della Sera daily.

Three-star chef Fabrizio Mellino from the Amalfi Coast restaurant Quattro Passi is responsible, according to the newspaper.

The main course is said to be Spaghetti alla Nerano - a family recipe with fried zucchini and the aromatic cheese Provolone del Monaco.

Dessert will reportedly be a lemon, ricotta and pear creation by Sal de Riso, a patisserie also located on the Amalfi Coast. The wedding cake, meanwhile, is to come from Paris.

Pizza dough barrels from the Neapolitan district of Rione Sanità have reportedly also been spotted - stoking speculation that up-and-coming pizza chef Ciro Oliva will be at work too.

Lavish sums, large protests

The wedding costs are estimated at at least $10 million. The President of the Veneto region, Luca Zaia, estimated them at €40 to €48 million ($47 to $56 million). He also claimed the event would generate an image boost for the region worth billions of euros.

Italian Culture Minister Daniela Santanchè estimated the overall economic effect of the wedding at €950 million.

The US billionaire donated €3 million to various city institutions according to his associates, an amount critics consider extremely small given his total wealth. The couple also asked their guests to forgo gifts and instead donate money for the restoration of Venice.

The up to €10 entry fee Venice charges visitors is waived for weding guests.

The wedding has triggered several days of protest. Critics accuse the billionaire of flaunting his wealth and of wanting to buy the entire city for a weekend.

On the Campanile, the iconic bell tower on St Mark's Square, the letters "FCK BZS" were projected with a laser installation, omitting the vowels needed to complete the obscene message aimed at Bezos.