Monaco's Royals Pay Tribute to Prince Rainier and Princess Grace During 'Secret' Ball

Prince Albert and Princess Stephanie were among guests in attendance at the event

Monaco's royals paid tribute to Prince Rainier and Princess Grace with a "secret" ball on Friday evening.

Held as part of this year's centennial celebration of Prince Rainier's birth, the evening — which proposed an "undisclosed location" — evoked one of the principality's most glamorous traditions: the midnight ball.

Friday evening's black-tie event began in the Casino Atrium, and featured Princess Stephanie, who has organized the Rainier Centenary, wearing a subtle homage to her mother: an Empire-waisted, champagne-colored, strapped gown.

Prince Albert escorted his sister, and also lending support for the evening benefitting the Fight Aids Monaco charity was Princess Stephanie's daughter, Camille Gottlieb, and her daughter-in-law, Marie Ducruet.

Following cocktails, guests dined beneath the gallery frescoes, which usually greet gamblers playing roulette, and the evening ended at the principality's Opera House, where guests enjoyed the very rare privilege of dancing on the theater's stage.

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Back in 1966, to honor the 100th anniversary of Monte-Carlo, Princess Grace attended the "Ball of the Century."

During the Second Empire-themed costume event, guests dressed in 19th-century fashion and period military uniforms, and gathered at the Monaco's Belle Epoque casino.

For the evening, Grace made a dramatic entrance and wore a high-waisted opera gown of pink silk and taffeta.

The authentically recreated Empress Eugenie-style dress descended into a full skirt featuring many ruffles, and the hem resolved the skirt into a fully rounded six-foot wide bell.

To complete her look, Princess Grace adapted a style she had portrayed onscreen in The Swan, and had celebrity hairdresser Alexandre de Paris arrange a crossover braid and a cascade of blonde curls, which flowed through a 1,040-stone diamond Empress-style tiara.

The diadem — attributed to the workshop of Marie Etienne Nitot and reputedly worn by Josephine for Napoleon's coronation — was loaned for the evening by Van Cleef and Arpels.

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With Prince Rainier on her arm, the white-gloved Princess Grace was followed by an entourage — a similarly attired princess court.

Among attendees curtsying to Grace and Rainier during the evening were Princess Aga Khan, Gina Lollabrigida, Curt Jurgens and perfume designer Helené Rochas.

Held in the spring, Bal de Siecle invited guests out onto the balcony and lawns overlooking the Mediterranean.

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