Watch for a secret surprise at Chelsea Clinton‘s hush-hush wedding to investment banker Marc Mezvinsky – her ex-boyfriend Ian Klaus will be honorary best man!

Despite recent press reports denying the Big Day is imminent, sources tell The ENQUIRER that the wedding is definitely on and will take place at Martha’s Vineyard in August.

On April 6, The ENQUIRER was the first to report 29-year-old Chelsea’s wedding plans to Marc, 31.

"They’re officially putting out word that there’s no wedding, but that’s just to confuse the media," a close source told The ENQUIRER.

"Invites will soon be going out by Federal Express, telling them all the details.

"The Clintons have worked out everything. All the rooms are booked. All the guests have to do is show up at their local airport, and they’ll be flown to the location.

"Every amenity has been thought of – right down to a selection of sunscreens for those who want to go to the beach before the sunset vows overlooking the ocean."

Guests will likely be surprised by the role of Chelsea’s ex-boyfriend Ian, who split up with the former first daughter in 2005.

"They’ve remained good friends after their breakup, and Marc likes and admires Ian and vice versa," said the close source.

Chelsea has often been spotted with her ex, a mop-haired former Rhodes scholar, along with her fiance at various events in New York.

Adding to the happy occasion, Marc’s father, former Iowa congressman Ed Mezvinsky, will also be able to attend since he was released earlier this year from a halfway house after serving time for investment fraud.

One source believes the wedding is going to take place at the Martha’s Vineyard mansion of Cheers star Ted Danson and his actress/wife Mary Steenburgen.

For ALL the DETAILS of the TOP SECRET happy event pick up the latest ENQUIRER on sale now!