London - Sometimes a dress is just a dress. But not in Kate Middleton's case.
Her wedding dress will be the symbol of her transformation from commoner to princess, from Kate to Catherine, and define her image to billions of people as they watch her exchange vows with Prince William next year.
This dress must be elegant, memorable and perfectly fitted. There are delicate balances to be struck: modern but traditional; alluring but not too sexy; classy but not overly opulent - more grown up than Princess Diana's famous meringue confection, with its puffy sleeves and almost 8m train.
Whatever the ultimate choice, expectations are sky high. Middleton has natural good looks and a radiant smile - people seem to wish her well, even if she will be able to afford a dream dress that is far beyond most people's reach.
"I'm not sure if she could pull off a Diana dress, but it would be great if she had something that magnificent," said Mary Alders, 32, a secretary who is looking forward to the royal wedding.
"Whatever it is, everyone will want it. I can see it as silk, maybe some beading. It definitely will be spectacular."
It's all a tall order indeed for a bunch of expensive material cut to fit a young woman's slender frame. But one designer - almost certainly one based in Britain - will soon get the nod for what is expected to be one of the defining dresses of our era.
Vanessa Friedman, style editor of the Financial Times, said the enormous significance of the dress, which will be copied throughout the world, makes it more difficult for Middleton, 28, to choose something simply because it looks great.
"It makes it impossible to pick something just because you like it," Friedman said. "Whatever she picks, it's not about her, it's about what they are going to become. It makes it much more political."
The unstated but very real pressure to pick a British designer, or at the very least a British-based designer, stems in part from national pride and in part from a desire to see a British company benefit from the inevitable "Kate effect" that will bring fame and prospective buyers.
The dress can be expected to shed the best possible light on the designer's entire collection and is likely to be widely copied in lower-priced versions that will be sold throughout the world, although it is likely the designer will not benefit directly from these imitations.
Insiders say that there would be a formidable backlash should Middleton choose, for example, an American or Italian designer. A French one would be all but unthinkable considering a history of bitter and sometimes bloody rivalry.
Now that an April 29 date has been set - with high hopes of fine spring weather - the guessing game about the choice of the designer, and the style of the gown, has begun in earnest.
The palace hopes to keep the designer and design top secret until that dramatic moment when Middleton walks down the aisle.
Like any bride, Middleton will want to maximize the impact of her arrival.
The age of instant internet communication and the constant presence of people carrying cellphone cameras will make this goal more difficult, so it is likely that designers will be smuggled in to see Middleton with strict orders to avoid attracting attention.
She will have as one of her guideposts the stunning antique lace, silk taffeta and tulle wedding gown worn by actress Grace Kelly when she married Monaco's Prince Rainier in 1956. That unique creation has set a standard for royal weddings that has been difficult to match.
There are other pressures now as well. London model Erin Saltman said Middleton should consider choosing "green" bridal fashions that have caught on in recent years - an approach that would undoubtedly please Prince Charles, the environmental activist who will be her father-in-law.
She said you can choose wedding gowns made of organic and ethically sourced material "without looking like a hippy burlap sack".
Saltman said the bride should avoid Diana-like touches, like a long train or puffy sleeves, and should consider a small, simple veil - an idea some in the public share.
"I'd love to see her in a very simple dress," said Sandra James, 40, a cashier in an Oxford Street department store.
"I'm sure there are rules for what you can and cannot wear in the abbey, but she'd look great in an off the shoulder, lacy dress.
"She dresses simply, so something simple and elegant would be perfect."
There has been much speculation that Middleton might choose Daniella Issa Helayel, a British-based Brazilian designer behind Issa London designs. Middleton has often been photographed in Issa's slim, colourful, sexy dresses, also worn by Madonna, Gwen Stefani, and other celebrities.
That choice seems unlikely to fashion experts, however, in part because of Helayel's Brazilian heritage but also because she does not normally make wedding dresses, although Issa plans to introduce a bridal line next year.
"I'd be very surprised if it's Issa," said Deborah Joseph, chief editor of Brides magazine.
"A lot of intricacy goes into making a wedding dress, you need an expert, not just a designer. Issa is known for very understated dresses, they're not about drama and grand entrances, and this one will have to make a grand entrance."
Stella McCartney is also a very unlikely choice, despite her prominence, because of her lack of experience with wedding gowns, Joseph said.
"If I were betting, I'd bet on Phillipa Lepley," said Joseph. "She's very popular with the Chelsea set already, she is very discreet, she is not flashy, she would get the mentality of a royal wedding, she'd be a safe choice - and she's British."
She mentioned longtime British fashion star Vivienne Westwood - now welcomed by the British Establishment, despite the provocative punk designs of her early days - and Jenny Packham as other possibilities.
Britain's ubiquitous bookmakers also think highly of Lepley's chances, making her the favourite when listed against other big name designers like Westwood and McCartney.
Her custom-made wedding dresses range from about £7 000 to about £26 000 depending on the material used and the amount of embellishment. Other top dressmakers are in the same general range.
But it is possible the dress will be given to Middleton for free, Joseph said, because of the tremendous global publicity that will be generated.