For her comeback concert at Carnegie Hall in March 1948, after 10 months in jail, Billie Holiday wore a long gown, gloves and that trademark gardenia. She was, as always, every inch the star. From those gowns on stage, to fur coats, ponytails and diamanté sunglasses offstage, Holiday oozed mid-century glamour.

Lee Daniels’ The United States Vs Billie Holiday is released this month. The film, starring Andra Day, focuses on Holiday at the height of her fame in the late 40s and early 50s when she was targeted by the FBI, after she started singing Strange Fruit, a protest song about lynching in the south. Seen by the agency as a troublemaker when she refused to stop singing what was seen as a controversial song, the FBI recruited Jimmy Fletcher, a rare Black agent, to bust Holiday – a known heroin user – for drug offences. Daniels’ film, using Johann Hari’s 2015 book Chasing the Scream as its basis, tells the story of that time. And style is part of that story.

Paolo Nieddu, the costume designer on the film, said he began researching the wardrobe by putting together a scrapbook of images. “I focused on finding as much as I could on her during that time, but I went back further just to help me get a sense of all of her style elements,” he says. “What did she wear in the 30s? What did she wear in the early 40s? You’d find pictures of her out at dinners, smoking at a table, sitting with Hazel Scott and other jazz musicians.”

Nieddu was stuck by how experimental Holiday was with her clothes. “I would look at her and be like, ‘What year is this?’” he says, “[or] she’s not wearing a bra at a time when undergarments were so regimented”. He points to her penchant for diamanté sunglasses: “You’re like, ‘These glasses are wild.’”

Perhaps it was Holiday’s avant-garde reputation that drew Prada to the film. Nieddu worked with the brand on eight outfits, including a yellow satin dress with sequins that – along with the ponytail – is bound to become a reference for new Holiday fans. It was a bucket list kind of collaboration. “I would show them a dress and find an archive and say, ‘I love the sleeve from Resort 2011 but can you make it into a gown and make it yellow?’ And they were like, yes,” says Nieddu. “It was crazy – it was literally like customising Prada pieces.”

Daniels’ film is partly focused on Holiday’s drug use, and this had an effect on her style. Nieddu points to the long gloves, “an iconic fashion element of Billie, but the real truth behind it is to hide needle marks. There’s a total pathos in her style in some way.”

Crucially, Holiday, in Daniels’ film and in images from the time, never conformed to the stereotypical image of a drug addict. Instead, she enjoyed fashion and had a performer’s joy in being looked at, in satin, silks, heels and hairstyles, until the very end of the film. Perhaps, for Holiday – who suffered abuse as a child and was no doubt traumatised by her persecution by the authorities – clothes were a kind of armour. At one point in the film, Miss Freddie, Holiday’s close friend, tells Jimmy Fletcher: “She looks like a million bucks but fees like nothing.”

But, for a Black woman in the US at that time, this glamour could be seen as a kind of resistance, too. That was certainly an idea that Day saw in her character. “It’s important, when we talk about her fashion, that we remember how radical it was for a Black woman to be in her position during that era,” the actor told Vogue. “Mainstream society had a problem with seeing Black women in the context of success. In those days, uppity was still part of the vernacular. People said, ‘How dare she wear diamonds, how dare she wear fur,’ but she dressed as a woman of her stature should have. She represented herself exactly as she wanted to and that in itself was revolutionary.” See Holiday in full star regalia, photographed at a court hearing in San Francisco in 1949.

As the singer acknowledged, racism was still there, no matter what you were wearing. Speaking about gigs in the south, she said, “You can be up to your boobies in white satin, with gardenias in your hair, and no sugar cane for miles, but you can still be working on a plantation.” Nevertheless, she persisted – and her sheer head-turning visibility contributed to her persecution. Federal agent George White, who also investigated Holiday, found her style to be part of what made her so dangerous. “She flaunted her way of living, with her fancy coats and fancy automobiles and her jewellery and her gowns,” he said. “She was the big lady wherever she went.”

There was a certain defiance across all elements of her life, says Nieddu. “The avant garde in her, I don’t know if it came from the way she viewed things,” he says. “Being unafraid to sing [Strange Fruit] shows you this woman is fearless and risk-taking. I think it translated into not only her music, but it went into her style.”

The United States Vs. Billie Holiday is on Sky Cinema from February 27th