When the New Zealand soprano Kiri Te Kanawa walked on to a Cardiff stage to present the Ukrainian baritone Andrei Kymach with the BBC Cardiff Singer of the World 2019 award, she did so wearing a bedsheet. The watercolour flower cotton flat sheet from Zara Home, to be precise.

“I have been looking for a hydrangea print for years,” she told reporters. Stumbling across this pattern, she said, felt like the answer to her prayers. A dressmaker fashioned it into a full-length skirt with a blue satin trim. “It’s Dame Duvet,” shouted the tabloids, predictably.

Now, while the shiny ribbon around the hemline puts the garment firmly into the homemade partywear bracket – it looks exactly like a flower-girl dress I had to wear to a wedding when I was six – the idea itself isn’t a bad one. I’ve been making dresses from bed linen for years. Vintage linen sheets are particularly good: starched and robust, they hang beautifully. So I figure this one might work too.

I can’t find Te Kanawa’s hydrangeas, but I do find another sheet in the range with a fruit and butterfly print. It looks pretty good inside out, too, so I decide to use it both ways. I’m not wild about such big flowers on my clothes, but if I channel the Japanese designer Rei Kawakubo, there must be a way to make something cool with it.

I opt for a Molly Goddard-style oversized dress pattern that a friend – Val Hui of Otho London – cut for me a while back. I was going to a wedding, and all the dresses I liked cost thousands of pounds. Dresses so simple they were essentially a kid’s drawing of a dress – sleeveless top, round neck, A-line skirt. You’re having a laugh, I thought, and decided to make my own. That one was navy blue silk. I wonder how bright white cotton is going to look, and decide I’ll leave edges raw, to offset the chintz.

The finished article. Photograph: Graeme Robertson/The Guardian

One of the good things about big sheets is precisely that – they are very big pieces of fabric. This one is 240cm x 280cm, which – for a full-length skirt, an oversized dress or anything involving pleats or gathering – is useful. You’ve got a lot to work with. This is thin white cotton, so it’s definitely going to be see-through. After I’ve cut out the top, I use two lengths of the full width of the sheet for the gathered skirt, so that I can double up the layers in place of a lining.

Riffing on the way Comme des Garçons dresses often use messy, scrunched-up wads of fabric as trim or texture, I add an extra length of pleats around the waistline and hemline and leave the neck and armholes unhemmed. Also, I made this in three and a half hours flat, so there wasn’t time to hem anything.

But that is the other good thing about working with bed linen – it’s very strong, durable fabric and it has already been professionally hemmed. So any way you can incorporate those hems into your garment is a winner.

I greet the photographer at the door wearing the dress, only for him to look around for what we’re shooting. “Oh,” he says when I tell him this is it. Which I guess is good – he was briefed about a bedsheet, but all he saw were my clothes.