The future Duchess of Cambridge was wearing an intricate ivory satin dress, with lace floral detail, designed by Sarah Burton, of the Alexander McQueen fashion house. The gown - dubbed by fashion experts "the wedding dress of the century" - reportedly cost GBP250,000 (about HK$3 million).
Hongkonger Mimi Chan Wai-han was one of two dozen of the best embroiderers at Britain's Royal School of Needlework who realised Burton's vision. They meticulously hand-stitched onto silk the lace which had been made into motifs symbolising the nations ruled over by the royal family - the rose (for England), thistle (Scotland), daffodil (Wales), and shamrock (Northern Ireland).
Chan was the best and only Chinese student in the history of the school's diploma course.
"It was a huge honour for an ordinary woman from Hong Kong like me to be involved in the historic project," says Chan. "I felt as if I'd won the jackpot."
For months, the team worked in the strictest secrecy to create the lace applique. Chan said workers washed their hands every 30 minutes to keep the lace and threads pristine, while the needles were renewed every three hours, to keep them sharp and clean.
Still bound by a confidentiality agreement, she cannot reveal how many people worked on the project, or how long it took.
Chan fell in love with embroidery as a child, when making dolls' clothes with bits of fabric given to her by her mother, who made the family's clothes.
Yet it wasn't until two years ago that she took her favourite pastime more seriously and signed up for a year-long course at the royal school at Hampton Court Palace in London to master techniques such as blackwork, a form of embroidery using black thread, and silk shading, or "painting with a needle".
She says: "I love the serenity of sewing - sitting by the sash window in brilliant sunlight in the apartment I had in England."
Lessons were held in an enjoyable, relaxed atmosphere - until it came to assessment. Her teachers were perfectionists and any error, such as a loose stitch, stain or puckering of the fabric, could cost a mark out of 10.
"We students joked that they scrutinised our work with magnifying glasses," Chan says.
However, Chan never feared the assessments. She always aimed for standards higher than those set by teachers; one teacher called Chan "fussy" because she would "start her work all over again if one stitch was 0.0001mm away from the ideal spot".
Chan says: "It might seem to be working backwards, but it's not a problem. If you take all the imperfect stitches off and spend one extra morning sewing, you can produce a much better piece."
It is "hugely rewarding" to see one's embroidery work come to life, even if it is time-consuming, she says. It can take 12hours to sew only one 2cm-by-2cm area of embroidery; an A4-sized portrait, crafted from blackwork, can take at least three weeks to finish.
Such work also means the hands of a typical seamstress - including her own - are far from the beautiful ones depicted in period television dramas, she says. Her hands suffer from calluses, soreness, bruises and peeling skin caused by repetitively pulling threads from fabrics that can be as thick as canvas.
After graduating last August, she set up the Tour Embroidery school and studio, in Wan Chai.
To learn canvas-stitching from Chan for free, sign up for the Hong Kong Young Embroiderer Programme. Applications close tomorrow. For details, go to www.tourembroidery.com