It has been signed by more than 200 stars including Billie Eilish, Leonardo DiCaprio and Joaquin Phoenix, and even inspired the Hollywood actor Laura Dern to plan a trip to the windswept shore of Dungeness in Kent when she is next in Britain.

Now the cream calico suit worn during the awards season by the Oscar-winning British costume designer Sandy Powell is to be auctioned in an attempt to raise money to save Prospect Cottage, the Dungeness home and garden of the late Derek Jarman.

The Art Fund charity is trying to raise £3.5m by the end of the month to protect the home of the film-maker, artist and LGBTQ+ activist. While 75% of the total has been raised, much of it through private donations, there remains £850,000 to go in just three weeks.

“It ended up being much more successful and fun than I ever imagined it to be,” Powell said of the autographs during a private viewing of the suit on Wednesday.

The designer, who was nominated this year for Bafta, Oscar and Critics’ Choice awards for her work on The Irishman, attended parties armed with a permanent marker and her “blank canvas” suit. Billy Porter, Janelle Monáe, Daniel Kaluuya, Adam Driver, Spike Lee, Renée Zellweger, Bong Joon-ho, Elton John and Saoirse Ronan are among the stars and luminaries to have signed the suit’s arms, legs and pockets.

Janelle Monáe signing Sandy Powell’s outfit at the Oscars. Photograph: Mario Anzuoni/Reuters

“A lot of people didn’t know who Derek was and they looked it up and expressed an interest,” Powell said, adding that Dern in particular “went away, looked on the website” and would now be one of the tourist visitors to the barren Kent headland.

Jarman bought and moved into the Dungeness cottage in 1986 and turned it into an artwork in its own right. After his death in 1994, it was cared for and maintained by his long-time companion Keith Collins, who died in 2018.

Powell said it was “like a mini-museum. It’s a gorgeous place. When he bought it in the mid-80s some people thought he was completely nuts. It was bleak, it was deserted, there was a power station right there … [but now] it’s filled with his work, with all the books that he read, books that he wrote and his diaries.” She said the garden was created “out of nothing but shingle and sand”.

Powell has described how some parts of the suit were 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. Robert De Niro and Al Pacino are on the lapel, Kylie Minogue peeps out of a pocket, and Donatella Versace opted for the back.

It “made going to the Baftas, going to the Oscars – I know it sounds really blasé, but actually it’s really boring a lot of the time – really fun and gave a purpose”, Powell said.

A closer view of Powell’s suit. Photograph: Matt Alexander/PA

She described the project as deeply personal – she credits Jarman with giving her a start in the industry and said he was the biggest influence on her career.

Tilda Swinton, a longtime friend and collaborator of Jarman’s, who was one of those to first approach Art Fund for their help, was also present at the private viewing to add her signature.

“Of course what we dream of is that some incredibly inspired and inspiring and enlightened rich person will buy this suit and give it to some museum,” Swinton half-joked. “It’s really important to remember that Derek was all about process, he was not really about things.”

The money raised will also go to fund an artistic programme of residencies. “We were the lucky babies who got to do it with Derek,” said Swinton, “and we visualise so many more lucky babies out there who can plug into the battery as well.”

The suit is being auctioned by Phillips auction house and will be on display at the front reception of Phillips Berkeley Square in London until the end of the auction at 5pm on 11 March.