'Costume-maker Jane Law and I achieved that with the choice of fabric and by using many different shades of shimmering blue,' explains designer Sandy Powell. Photo / Jane Law, Daily Mail
Cinderella - played by Downton Abbey's Lily James - has to dance and run away into the night, and I wanted the dress to look as light as air, a watercolour in motion.
Costume-maker Jane Law and I achieved that with the choice of fabric and by using many different shades of shimmering blue.
Behind the many layers, the gown is a feat of structural engineering. We started with the underwear: the corset and the crinoline (skirt cage), which was made of steel.
Each of the eight versions of the gown is also slightly different.
One was 2in shorter and a couple were 4in for the times when Lily had to run; another had holes cut in the sides of the skirt for harness work.
The hems got incredibly dirty as the shoot went on. That proved a headache - these dresses aren't something you can just throw in the wash.
And it also wasn't the most practical design. During filming, Lily and Helena Bonham Carter, who plays her fairy godmother and wears an equally huge gown, had to get used to it taking an age to be dressed.
• 4,000 Hours it took to make eight different versions of the gown
• 10,000 Swarovski crystals hand-applied to the dresses
• 20 Minutes it took to get the dress on
• 4 Inches one dress was shortened by to help Lily flee the ball at midnight
• The trickiest thing Lily had to do in the gown was dance with her prince, played by Richard Madden.
They practised endlessly, but poor Richard kept treading on her hems. Of course, when it came to actually shooting, they were faultless.
While I was delighted with the dress's reception, I was surprised by the obsession with Lily's tiny waist. People seemed to think it was setting a bad example to young girls. Some even accused the studio of digitally altering it. Ridiculous.
The reason her waist looks tiny is because the skirt is so huge - it's an optical illusion - and she's wearing a corset. The film is set in the 19th Century and every woman in the film is wearing one, even the maids.
I understand people get upset when incredibly skinny models appear on the catwalk or in photos. But Lily is not a super-skinny girl - there's nothing wrong with her body. Cinderella is a girl known for kindness and courage, so it's sad people just kept talking about her waist size.
Despite the sniping, the dress was everything I hoped it would be.