Kate Middleton’s wedding dress was only revealed during her wedding day to Prince William on April 29, 2011.

Prior to the couple’s nuptials, there were speculations as to who will be designing her gown and how it would look like. But the Duchess of Cambridge’s dressmakers saw to it that no information about the royal’s attire will be leaked to the media ahead of her big day.

During a recent interview, dressmaker Mandy Ewing said that she and her fellow dressmakers know who the gown that they were making was for, but they were sworn to secrecy.

“We had net curtains up and cleaners were not allowed into the room and the code on the door was changed,” she said.

Ewing also said that she and the other dressmakers had such a fun time creating Middleton’s wedding dress because it was a once in a lifetime experience. It has been a common practice for members of the royal family to not reveal the name of their designer until their wedding day.

Last year, the identity of Markle’s wedding dress designer was only revealed on the day of her nuptials. Prior to her special day, there were tons of speculations on who will be designing her dress. Some experts even thought that Markle’s gown will also be created by Alexander McQueen.

Several years ago, details about Princess Diana’s dress were also kept under wraps. It has been said that the Princess of Wales’ iconic wedding dress was the most closely guarded secret in the fashion industry.

And other than Princess Diana’s main wedding dress and her gown for the wedding reception, her designer revealed in 2011 that the late royal actually had a third dress that day.

While speaking with People, Elizabeth Emanuel said that the backup dress was made in case of emergency and in case the design of the royal’s gown will be leaked prior to the ceremony.

“At the time we wanted to make absolutely sure that the dress was a surprise,” she said.

Kate Middleton Wedding Dress
Kate Middleton's wedding dress may have cost less than Meghan Markle's. Here, she is pictured arriving at the West Door of Westminster Abbey in London with her sister, Pippa Middleton, for her wedding to Prince William on April 29, 2011. Odd Andersen/AFP/Getty Images