Chelsea Clinton's July 31 Wedding at Opulent Astor Courts

The closely held details of Chelsea Clinton's wedding have begun to leak out, and the first major morsel may well be the venue.

She will marry investment banker Marc Mezvinksy, 31, at Astor Courts, a Beaux-Arts masterpiece overlooking the Hudson River designed in 1902 by famed architect Stanford White for American oligarch John Jacob Astor IV. From the outside, it evokes Louis XIV's Grand Trianon at Versailles. And inside? It's straight out of an Edith Wharton novel.

Speculation about everything from Chelsea's wedding gown (Vera Wang? Oscar de la Renta?) to the officiant (a Protestant minister? A rabbi? Both? Neither? ) to the honeymoon destination (still a secret) have been swirling around the publicity-shy only child of former president Bill Clinton and Secretary of State Hillary Rodham Clinton for months.

Never mind that the bride's publicist, members of her mother's inner circle, the Boston wedding planner and the owners of the 50-acre estate on the outskirts of Rhinebeck, N.Y., have zipped their lips about all aspects of the celebration. The venue story first broke in the Hudson Valley News on Thursday, based on a unauthorized tip from a local resident. The July 31 guest list is said to be a nice, round 400, with each invitee personally known to the bride, reports New York magazine.

Now 30 and a Columbia University graduate student in public health, Chelsea will marry a man she's known since she was a teenager living in the White House and attending Washington's swank, private Sidwell Friends School. Both were at Stanford University, but the romance did not escalate until the past few years. He is the son of two former Democratic members of Congress: Marjorie Margolies of Pennsylvania, defeated after a single term in 1994 for backing President Clinton's budget, and her ex-husband, Edward Mezvinsky of Iowa, who served two terms in the House in the 1970s, and was later sentenced to seven years in prison for masterminding $10 million in fraud schemes; he was freed in 2008 and remains on parole.

The nuptial couple announced their engagement just after Thanksgiving via e-mail, following numerous false reports they would marry last summer on Martha's Vineyard.

Astor Courts, two hours north of New York City, is easy to reach by train or car, and elegant enough to provide a picture-perfect wedding backdrop while sufficiently secluded to offer security and privacy for the high-level guests, said to include foreign dignitaries, top U.S. officials and boldface names from the social, financial, entertainment and political worlds.

Built as a sporting pavilion at the turn of the last century, this onetime playground for American aristocrats -- think indoor clay tennis court and Moorish-style enclosed swimming pool -- is now home to Hillary Clinton supporters Kathleen Hammer, a former Oxygen Media producer, and developer-businessman Arthur Seelbinder. The couple spent three years restoring the decrepit wreck, guided by architect Samuel White, a great-grandson of Stanford White. Celebrity photographer Annie Leibovitz lives down the road.

Although there has been speculation that the festivities will take place under a tent for added privacy -- who wants paparazzi shooting pictures from the other shore? -- the building's ornate 2,100-square-foot main hall, which looks like a Gilded Age ballroom, might work nicely for the ceremony.

What more could a 21st-century bride want?