It's being billed by as the pet wedding of the century and, if the woman behind it all has her way, it will break the Guinness World Record for the most expensive animal wedding ever.

The scene is New York City's exclusive Jumeirah Essex House hotel on the edge of Central Park where, tonight, Baby Hope Diamond, the adopted rescue dog of TV personality and animal rights activist Wendy Diamond, will say or, rather, bark, "I do," in a $6,000 custom-made wedding dress as her more than 250 guests enjoy a $5,000 sushi spread, and a $15,000 seven-piece orchestra.

It's a "fairy-tale" wedding estimated to cost nearly $250,000 and it was all orchestrated after a contest to find a partner for Baby Hope, the dog adopted by Diamond after her beloved Maltese, Lucky, died of cancer last month.

When Diamond learned that 15-year-old Lucky was near death, she began an online contest to find a new partner for Lucky to join her as the face of Animal Fair, the charity she founded after adopting Lucky in 1999.

Click HERE to see photos of Lucky.

Tonight's wedding was intended to be a last hurrah for Lucky, but now it will be Baby Hope saying "I do" to Chilly Pasternak, the Virginia poodle that won the online vote.

"The bride and groom do not need to sleep or live together," Diamond told Goodmorningamerica.com. "They just need to partner in and live on Lucky Diamond's inspirational legacy in helping animal rescue and welfare."

Vendors are donating their services to the black-tie gala so that all proceeds from the $250-per-ticket affair can go to the Lucky Diamond Critical Care Ward at the Humane Society of New York.

While expected attendees include "Real Housewives of New York" star LuAnn de Lesseps and Dylan Lauren, the owner of the Dylan's Candy Bar chain and daughter of Ralph Lauren, all eyes will be on Baby Hope and Chilly.

Making sure of that is wedding planner Harriette Rose Katz, who planned Billy Baldwin's wedding to Cheyenne Phillips, and Diamond herself.

"I'm working like a dog, like every maid of honor," Diamond said, adding she is not calling herself the mother of the bride, considering that Baby Hope is 56 in dog years.

Also pitching in are Floralia Decorators, the florists for New York's famed Waldorf-Astoria hotel, and Buddy Valastro, of TLC's "Cake Boss" fame, whose Hoboken, N.J.-based bakery has created a surprise wedding cake.

If the Guinness World Record is indeed broken tonight, it will not be the first world record held by Diamond and her dogs.

As the face of Animal Fair for more than a decade, Lucky earned a spot in the Guinness Book of World Records for the "Animal Most Photographed with Celebrities," with more than 360 photos of everyone from Betty White to Barbara Walters, all catalogued in the " Who Got Lucky?" column on the charity's website.