A royal element makes it more dreamlike

When Kate Middleton walks down the aisle later this month to marry Prince William, the would-be brides watching out there will almost certainly home in on her dress.

Bridal industry insiders expect her gown to be copied many times over as soon as the public gets its first glimpse.

Some wedding dresses leave a legacy beyond the next-day knockoffs: Princess Diana's grand gown, Grace Kelly's glamorous one, Carolyn Bessette Kennedy's simple tank — and especially Queen Victoria's white ball gown — changed the way brides dressed for years to come.

Middleton's is likely to fall into that category.

"Kate's dress will be an important dress, one that will be talked about for the rest of time, " says Millie Martini Bratten, editor-in-chief of Brides magazine.

Diana's dress helped define the grandeur of fashion in the early 1980s, Martini Bratten says, but Middleton's might be even more influential because women relate to her as a 29-year-old with a developed sense of style, compared with the 19-year-old Diana, whose gown likely was chosen by committee.

Also, pictures of Middleton's gown will immediately be posted online for discussion and critique, notes Darcy Miller, editor in chief of Martha Stewart Weddings. "It's amazing how much brides are influenced by what other people wear, especially royals, celebrities, presidents' daughters. Before Chelsea Clinton's wedding was over, every bride saw that Vera Wang dress and wanted some version of it, " Miller says.

Celebrity red-carpet looks are adapted for the aisle, says Marchesa co-founder and designer Georgina Chapman, but many women have been thinking about their fantasy gowns for a long time and don't turn on a dime. "Wedding gowns are unlike any other dresses, " she says, because brides' decisions "are often less trend-driven, and more personally focused on how they want to look and feel on their wedding day. "

Still, a princess holds particular sway because of the fairy-tale aspect of weddings.

"A royal element makes it more dreamlike, and a wedding day is your time to look like a princess, " says Kimberly Lee Minor, chief fashion strategist of the bridal label Priscilla of Boston, which made gowns for the daughters of Presidents Johnson and Nixon.