Parisians are preparing gourmet picnic hampers and all-white outfits for a meal at a location that only will be revealed at the last minute.

The 30th anniversary of the international dining event known as "Diner en Blanc," or "Dinner in White," is being held in the French capital on Sunday night.

Organizers expect 20,000 to 30,000 participants, one-third of them from outside France. The Champs-Elysees avenue, the Louvre museum and the Eiffel Tower are among past sites.

This year's location is being revealed in a series of text messages.

Francois Pasquier, who launched the event in Paris in 1988, says more than two dozen orchestras are set to entertain guests. He concealed other details to maintain the mystery.

Last year, over 110,000 people in 28 countries participated in the events.