Aucoin died in 2002, at the age of 40, due to organ failure after he become addicted to painkillers. But in the preceding couple of decades, he became the first true celebrity make-up artist, as much of a star as the luminous faces he regularly worked on. He pioneered the art of contouring long before it was a thing with celebrities such as Kim Kardashian.

Since his death, no other make-up artist has come close to his level of celebrity; Mario Dedivanovic, known predominantly as being Kim Kardashian’s make-up artist, has many Instagram followers (5.2 million) and Pat McGrath sits at the top of a growing pile of ambitious, boundary-pushing artists, known for her use of brilliant colours and artsy flourishes.

But Aucoin’s celebrity extended well past the cloistered confines of magazine shoots and film sets. He appeared on talk shows, he wrote books and inspired many others.

The launch of his seminal 1996 book, The Art of Make-up, virtually shut down a New York street, an entertainment reporter saying on camera that she had never seen anything like it; guests included Ru Paul and Mary Tyler Moore, and Aucoin walked into his own party on the arm of Janet Jackson.

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The film documents all this, and more, starting from Aucoin’s modest beginnings in his hometown of Lafayette in Louisiana, where he was the adopted son of a happy, average family with three other siblings, all of whom were also adopted. Some of his family members make frequent appearances in the film; Tiffany Bartok says that Aucoin’s close relatives “went through a lot of healing through this.”

Tiffany Bartok says her job was made that much easier by all the pre-existing footage and photographs; when he was young, he would do make-up for his sisters and take Polaroids, many of which have been preserved.

“He always had his camera with him,” she says. “And what was even more interesting was what he would say when the cameras weren’t on him. He desperately wanted to talk about other things than make-up – the state of the world, politics, advocacy, diversity – and the lack of it.”

Cosgrave says that the film has been so well received – it hit number one on iTunes right after its release – partly because of how much the world of beauty today “is so enmeshed in social media”.

“It might be about a niche subject in fashion, but Tiffany has made it so relatable,” she says. As a former beauty editor herself, Cosgrave met Aucoin twice.

“He was always the one I couldn’t get to,” she says, adding that – in true rock star fashion – he always had an entourage around him. Both of her interview opportunities came up at the last minute; she remembers being just about to leave Paris, when she got a call from Aucoin’s team saying, “he can talk to you now.”

“It was backstage at a big show, and there he was, in his undershirt and with his perfect body.”

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The film charts Aucoin’s surprising rise; at 18, he got a job in the beauty section of the local department store – but customers weren’t comfortable having a man do their make-up. A subsequent move to Baton Rouge also didn’t work.

Soon after, Aucoin headed to New York, where he initially worked for free, doing the make-up on test shots for models. Some of those photos made their way to the editors at Vogue, who were entranced by Aucoin’s bold, definitive style. Recognising they had an emerging star on their hands, they introduced him to star photographer Steven Meisel, with whom he worked on several shoots, including covers.

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By the late 1980s, he was commanding thousands of dollars for a make-up session (which, given his perfectionist tendencies, could run to eight hours), and was often booked months in advance, criss-crossing the globe constantly. As veteran fashion editor Polly Mellen said of him, “Kevyn is what every make-up artist should be.”

The film also highlights Aucoin’s street smarts and wit.

“His sense of humour really surprised me, and his level of intelligence,” says Tiffany Bartok. “Make-up artists were not that worldly. But he was stuck in Louisiana for so long, and the film showed me how much he wanted to know about the world, how he was a worldly person who could adjust to any situation. Because of his intelligent advocacy and generosity, he had all these little quirks he could get away with. He was once working in France and was so hot that he insisted production have nine air conditioners flown in to him.”

And for Tiffany Bartok, meeting the eventual subject of her film, years earlier when she was 21, is a memory that will always stay with her; he was going to be playing himself on an episode of Sex and the City, and a friend of hers who worked on the crew asked if she’d like to meet him.

“It was behind a dressing room curtain and I was like a screaming fan. But he was so gracious,” she says. “He really took time away from his celebrity.

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“He was everything in one, and I don’t think you find that enough – the personality plus the talent, the one who does the sound bites and is infectious on camera, but who is also sincere, and who makes the person who is getting their make-up done feel safe and ready.

“And then he was also a family man, and that hysterically funny person that you don’t want to ever leave.”