Throngs of well-wishers and celebrity watchers gathered at Rhinebeck's main crossroads for a glimpse of the A-list guests who were staying at the Beekman Arms inn before the exclusive party at a mansion outside town.
As excitement mounted, growing numbers of limousines with tinted windows rolled through the streets, while staff could be spotted delivering elaborate dresses in dry cleaners' bags to local hotels.
The bride's parents -- former Democratic president Bill Clinton and Secretary of State Hillary Clinton -- arrived on the eve of the wedding. Other guests were expected to include the likes of TV chat show queen Oprah Winfrey.
"This is exciting. There's so much trouble in the world but this Saturday everything stops just for this wedding," said Anne McConnell, who had secured a strategically placed bench opposite the Beekman in hopes of seeing members of the Clinton family.
"It's just a shame it's not on TV," she said. "This should be live on TV like Princess Diana's wedding."
There was no chance McConnell's prayers would be answered.
Chelsea, 30, and Mezvinsky, 32, prepared their nuptials in the kind of secrecy usually reserved for affairs of state.
The wedding itself was taking place in the high-security seclusion of Astor Courts, an estate just outside Rhinebeck, about 100 miles (160 kilometers) north of New York city. Up to 500 guests are expected.
Authorities declared a no-fly zone to prevent paparazzi photos and police turned out in force. Officers blocked access to the Astor estate and squad cars, lights flashing, raced down the two-lane rural road outside, while other police vehicles could be seen tucked away down leafy side roads.
Even the location had not been confirmed right into this week, while details such as the designer of Chelsea's dress and the guest list were still unknown to the public on Saturday.
A different sort of mystery was whether a minister or a rabbi -- or both -- would preside, since Chelsea is a Methodist and Mezvinsky is Jewish.
Ironically, the news blackout fed an ever greater media frenzy. News teams from Japan to Israel flooded Rhinebeck, joining amateur wedding watchers, all asking the same questions.
"I want to know what dress Chelsea's wearing -- and Hillary too," said local Chris Madden.
"I want to know what's on the menu," said Walter Mullin.
Reports from gossip websites such as TMZ and tabloids like New York's Daily News painted a picture of an extraordinarily lavish occasion likely to cost three to five million dollars.
That included renting Astor Courts, an elegant white building near the Hudson River commissioned a century ago by John Jacob Astor IV, a tycoon who died on the Titanic.
Chelsea is believed to have ordered a dress from top fashion designer Vera Wang, while just the air-conditioned tents erected for the day are estimated to cost 600,000 dollars, with the floral arrangements only slightly less.
Although guests were given strict instructions not to disclose invitations, they were reported to include Winfrey, Hollywood mogul Steven Spielberg and possibly former British prime minister John Major.
President Barack Obama was not there -- he says he was not actually invited and that in any case two presidents would be one too many at a wedding.
Joining in the stonewalling, staff at the Beekman Arms were refusing to respond to journalists' questions about guests after having reportedly signed confidentiality agreements.
That left locals to gossip on street corners or the local diner, Pete's Famous Restaurant, and to cheer at the sight of a couple parading around town in Bill and Hillary rubber masks.
One family set up beach chairs on the grass verge outside their house opposite the Astor Courts entrance. "We have front row seats," said Rachael Scorca.
Others, unable to join the real festivities, instead dressed up their dogs. Pooches decorated with white ribbons, a dog-shaped tuxedo and in one case even a white veil, were just part of the increasingly exotic scene.
For the ultimate fall back, there was always the T-shirt -- a white number retailing at 25 dollars and inscribed "The Wedding, Rhinebeck, NY," with a picture of two interlocking rings.
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