Royal Wedding: Proper Guest Attire for Prince William and Kate's Big Day

Invited royal wedding guests are expected to follow some rules for the event.

ByMARY PFLUM, BIANNA GOLODRYGA and NICK WATT
April 27, 2011, 11:31 PM

April 28, 2011— -- There has been endless speculation about what princess-to-be Kate Middleton will wear on the big day.

But what about the guests?

On Friday, 1,900 lucky guests will convene in Westminster Abbey for the royal nuptials .

Determining what to wear to such a high-end, globally watched affair is no easy matter.

Indeed, some have called dressing for the royal wedding a fashion minefield where one wrong step can -- and will -- land an attendee on a worst-dressed list for years to come.

ABC News went to high-end London-based department store Selfridges for help with the matter.

Because the wedding will take place at Westminster Abbey, leading Selfridges stylists said, sleeves for women are a "do" and looking too sexy is a "don't." Exposing shoulders in a sacred house of worship is considered improper.

And while it's important to look proper, it's ill-advised to appear stuffy. Too many frills or too high a collar can be considered fashion-backward.

Watch a special "20/20" today at 8 p.m. ET for a behind-the-scenes look at the life that awaits Kate Middleton, and tune in again at 4 a.m. Friday for ABC News' live coverage of the royal wedding with Diane Sawyer and Barbara Walters.

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