When the Oscar-winning British costume designer Sandy Powell found herself with a Bafta nomination for The Irishman, she thought: “What on earth am I going to wear?”

What she ended up creating was not just a unique walking work of art, but also a way of helping preserve the former home of her mentor and close friend, Derek Jarman, the late film-maker, artist and LGBTQ+ activist.

In keeping with the Bafta theme of sustainable fashion, Powell chose to hit the red carpet in a cream suit toile – a calico template from an earlier designer suit. Powell, a three-time Oscars and Baftas winner, said: “Then I thought: ‘It’s like a blank canvas. I could go armed with a pen, and get signatures. And maybe we could auction it.”

And so it was that she dreamed up a way to help save Prospect Cottage, Jarman’s home on the windswept shore of Dungeness, Kent, which he had transformed from a Victorian fisherman’s hut and from where he created some of his best work.

Powell strode forth among A-list celebrities at the London Critics’ Circle and Bafta awards to secure the signatures of more than 100 Hollywood stars and luminaries from the film and theatre industry.

Robert De Niro signs Sandy Powell’s suit.

“I think I’ve done pretty well. I’ve got Robert de Niro, Al Pacino, Joaquin Phoenix, Scarlett Johansson, Renée Zellweger, Laura Dern … I’ve got all the winners, so far,” she said. “But I need to get Brad Pitt and Leonardo DiCaprio. There are a few big names missing.”

So this weekend, she and the suit will head across the Atlantic to the Oscars. “I won’t wear it to the ceremony itself, but maybe to one of the parties. But I definitely want to get Martin Scorsese, who has agreed to do it,” she said.

Some parts of the anatomy are less signature-friendly than others. Richard E Grant had to kneel down on the red carpet to add his name, while Gwendoline Christie found herself signing Powell’s inner leg.

“I was quite choosy about who signed where,” said Powell, who has won Oscars for Shakespeare in Love, The Aviator and The Young Victoria.

Powell with Richard E Grant.

The result is a unique piece to be auctioned through the Art Fund charity, which is trying to raise £3.5m in 10 weeks to save Prospect Cottage and its stunning garden. Expressions of interest can be registered at development@artfund.org with details of the auction still to be announced.

“It’s not just important as a piece of history, but also to preserve his legacy,” said Powell, who became close friends with Jarman after he hired her to work on Caravaggio. “It is so important Derek doesn’t get forgotten, and that he can continue to inspire young film-makers, artists and writers.”

Jarman moved to the cottage in 1986, turning it into an artwork in its own right, filling the garden with sculptures made from flotsam and jetsam. After his death in 1994, it was cared for and maintained by his long-time companion Keith Collins, who died in 2018.

The artist Tacita Dean and actor Tilda Swinton approached the Art Fund to come to the rescue. The £3.5m is needed to purchase, preserve and maintain the property as a place for artist residencies and public access. Creative Folkestone, an arts charity, will manage and maintain it. Jarman’s archive of documents and artefacts will also be available to the public at Tate Britain.

Art Fund spokeswoman Rachel Mapplebeck said: “Derek Jarman’s Prospect Cottage is really a work of art in its entirety. The cottage is full of works of art by him and his friends. There are props from film sets. It’s surrounded by this incredible garden, which he created from the shingle beach.”

Half of the £3.5m has been raised by private donors. The remainder is being crowdfunded through the Art Fund website, with many artists offering rewards in exchange for donations.

Powell “hasn’t the faintest idea” how much her suit could raise. But she said: “It would be nice if it ended up in a museum, or somewhere where other people could see it.”