His aim is not just to investigate how our prehistoric ancestors made textiles, but also to ask vital questions about humanity's relationship with nature in a time of climate crisis.
Howitt – who's been
twice nominated for a BAFTA, for his BBC series
Matters of Life and Death and the children's series
Rooted for Channel Five – has filmed Brown's progress from the beginning.
Three short videos he made with Allan went viral and clocked up millions of views.
They inspired the creation of the
Nettles for Textiles Facebook group, a vibrant international community of more than
16,000 crafters and makers.
He is now
seeking funding to create a
30-minute documentary about the project, with plans to have it shown in cinemas.
Every thread Brown creates represents weeks of work.
He walks in the South Downs to harvest the nettles, then strips and softens them to extract fibres that can be spun and woven.
All those hours, days and seasons of labour have resulted in just a few dozen skeins of precious thread for his loom.
He aims to complete the dress – which will be based on a Viking design – in spring 2021.
"This is the slowest of slow fashion, a real labour of love to create an iconic object," explains Allan Brown.
"The idea came to me because I wanted to see if it would be possible to make wearable cloth by hand from freely-available local plants.
Nettles for Textiles
"I wondered if this was the first cloth our Neolithic ancestors made and, if so, how on earth did they do it?
"I decided to use only the kinds of tools available to them at the time.
"It's not just about looking to our past though. I also want to see if nettle fibre can play a role in helping us develop more sustainable and ethical ways of making clothes – harnessing the power of the natural world around us and, thereby, becoming more in tune with it."
Dylan Howitt adds:
"In the documentary, I plan to show the complete process of making the dress, from the plant to the loom – set against the stunning backdrop of the changing seasons of the Sussex countryside.
"The film will be a vivid 'how-to' guide, showing Allan searching out and working the nettles – and taking us through what he's learning, in a film as carefully crafted as the dress itself.
"I'll also weave in conversations with other makers from the Nettles for Textiles community.
"We'll reflect on philosophical lessons learnt during this extraordinary effort.
"Working so slowly by hand is transformative, bringing up different conceptions of time and questions of what constitutes value.
"I know there is an audience for this documentary, especially in and around Sussex.
"The short films we've made have had tremendous success, demonstrating a growing community of people who want to learn about nettles for textiles and discuss new ideas around sustainability in fashion and life.
"Any help local people can give, no matter how small, is hugely appreciated."