Chelsea Clinton's Wedding: The Inside Scoop

Chelsea Clinton and longtime boyfriend Mark Mezvinsky will wed this July 31.

The location is undisclosed, and the guest list of 400 for what may just be he biggest social event of the season is being guarded like a state secret.

But, Doree Shafrir, a New York Magazine contributing editor, got some inside info and shared it Tuesday with co-anchor Erica Hill on "The Early Show."

The wedding is rumored to be within a three-hour drive of New York City, rather than what was originally thought to be its setting, Martha's Vineyard. "So, the plan right now is for the wedding planner to let all the guests know a week before the wedding exactly where it is," said Shafrir.

When she was first daughter, the Clintons fiercely protected Chelsea's privacy. But from the age of 12, Chelsea has been in the spotlight, from her father's election, to his White House scandal with Monica Lewinsky, and again recently during her mother's presidential campaign.

Because of her private nature and for security reasons, leaks about the wedding are few and far between, says Shafrir.

The guest list of 400 may seem hefty, but it's been whittled down significantly, Shafrir says.

"The word is that if you don't know Chelsea personally, you're off the list," she explained. "So, she has to know everyone personally who is going to be invited, which of course eliminates a lot of people who only know Bill and Hillary."

As for the location, Shafrir said it's rumored that it will take place at a donor's place somewhere in upstate New York. That might be partly for security reasons, because it would be easier to assure tight security in someone's house.

It's also said that the ceremony will take place under a tent, which would give the bride and groom some extra privacy away from aerial views.

Chelsea and her investment banker boyfriend met as teenagers back in Washington, and studied together at Stanford University. The two have come a long way since: Chelsea is currently working on her Master's degree in Public Health at Columbia University.

And while wedding rumor is abuzz, the honeymoon plans are a complete mystery.

One more detail: It's rumored, says Shafrir, that the bride will be walking down the aisle in an Oscar de la Renta dress in a little over a month.