Designing a Royal Wedding Dress

LONDON, April 8, 2011— -- Sketching and design is just the beginning of the job for whomever will be picked to design the royal wedding gown.

The designer and his or her team will also serve as Kate Middleton's confidant, security advisor, style guru, not to mention both cheerleader and most critical eye.

There are only two women in the world who know what this job is like, and ABC News was lucky enough to sit down with both of them.

"There was absolutely no instructions or protocol from the palace," Elizabeth Emanuel, who designed Princess Diana's dress told ABC News.

"We kind of made it up as we went along. I think it was nice that they trusted us to do the right thing."

When Diana married Charles in 1981 there was no template on how a modern royal wedding should look, so Emanuel was very much part of the progress of figuring it out.

The first thing was protecting the dress.

"We cared about security so much that we organized for a big metal safe to be delivered to the studio," said Emanuel. "We had to hoist it up through the windows."

"Every night we would lock the dress up in there and we had to have security guards, Jim and Bert, and they had to guard it."

The next most important thing is to have a back-up plan.

"We would have gone with plan B and we had another dress on standby which was nearly ready just in case because there was no way we were going to let the identity of that dress come out before the big day," said the designer.

"We had another dress and we could have finished it in 24 hours if we had too...the main difference was it didn't have the big puffed sleeves, it had slim sleeves."

"We did try to prepare for any possible moment."

"We made an overskirt because wouldn't it be awful say if Diana was drinking from a cup of coffee and someone walked into her and spilled something down her dress."

What would happen, we made an overskirt to skip over the dress so you wouldn't see anything, smelling salts, safety pins, we doubled stitched over the zip to make sure it didn't break."

The designer was on tenterhooks as Diana travelled by carriage to St. Paul's Cathedral.

"We saw her head first, everything looked great, more and more of the dress showing, and when she reached the very top bit we realized how creased the dress was, I think my heart stopped."

But looking back now, and looking at the video footage, that bit reminds me of a butterfly coming out of a chrysalis. It gives me goosebumps when I think about it," said Emanuel. "It's my favorite image."

Five years later, and a different designer was faced with the challenges of a new wedding.

This time it was Lindka Cierach, chosen to design Sarah Ferguson's dress for her wedding to Charles' younger brother, Prince Andrew.

Cierach vowed to learn from the difficulties faced by Emanuel.

"We were at Buckingham Palace," Cierach told ABC News. "It was literally the night before.... She [Sarah Ferguson] looked amazing. She started walking from one part of the floor to the other and my heart was going ba boom ba boom ba boom because in actual fact the train veered off completely to one side!"

"So then we had to hurry, rush call to Westminster Abbey, and the poor carpenters were up all night hoovering so the carpet was all upright so the train would carry on down the aisle and not digress one way or the other."

So, it was emergency carpenters for this wedding!

Such last-minute mishaps can hardly be anticipated. But what about some advice for our princess-to-be?

"She will be a modern bride," says Cierach, "in the 80's when Diana's and Sarah's it was a flamboyant time, it was a time of dynasty, and these big massive shoulders, and really in your face dressing, female power. Right now it is more relaxed and subdued."

"She is going to go with who she is comfortable with and who can translate her dreams into reality," says Emanuel, "so nobody should dictate to her who she should or shouldn't have as her designer."

And what about the wedding day itself?

"If it is anything like Diana's it is going to be incredible," said Emanuel.