Miuccia Prada and Elsa Schiaparelli: In a league of their own

"We have a thing in Italy about women and cars," Miuccia Prada said backstage after the showing of her current collection.

It features ultra-feminine shapes – think circle skirts, pencil skirts, halter-necks and blouses – as well as more than a nod to the latter Italianate obsession: cartoonish engines bursting here and there into flames, which playfully undercut an otherwise decidedly womanly appeal. "Sweetness is a taboo in fashion and I wanted to combine sweetness, which is possibly the greatest feminine quality, with cars," the designer said.

It is true that of all the things we might expect from fashion – and of the formidable first lady of fashion, for that matter – sweetness is, on the face of it, the least likely. But Prada has spoken and, call it unfathomable designer intuition or just the obvious antidote to winter's more dark and androgynous looks, but everyone from Louis Vuitton in Paris to Christopher Kane in London appears to be in line with her way of thinking. Despite such elevated company, Prada pulls it off with a lighter touch than most.

The secret of her ongoing fascination with a stereotypical mid-20th century bourgeois silhouette is, invariably, to tweak and edit it and, of course, treat it with the hefty dose of irony it is due. That is by now as much one of her signatures as a nylon rucksack or fine leather bowling bag. From the designer's so-called "sincere chic" spring/summer 2000 collection forward, an exploration of the clichés of the woman's wardrobe – lip prints and roses, leather and lace – have both surprised and, at times, confused not least because wearing them in a less-than-knowing manner might bring out the frump in even the most dapper dresser. It's no coincidence that Prada herself, who has wit, intelligence and elegance in spades, is the finest poster girl for her own designs

In particular, this designer is in love with the skirt. She has said in the past that although trousers might reduce her apparent weight by a good kilo or more she prefers the more ladylike staple. Making fashion simply to flatter is, by her reckoning, banal. Prada loves skirts so much – be they dirndl, straight, car-wash pleat, long or so short they barely qualify – that, in 2006, she devoted an entire exhibition to them. Entitled "Waist Down", it showcased everything from Prada skirts finished with crushed bottle tops (she called this "trash couture") to more printed with designs inspired by vintage-Formica worktops, and from tufted alpaca skirts – which the designer herself described merrily as "fattening" – to "porno chic" designs, skin-tight, split-to-the-thigh garments that whispered of the work of Allen Jones.

Is Prada obsessed by skirts – which feature in almost every look of her current offering – because she is a woman? Certainly, a consciousness that she is a considered and clever female working at the heart of an industry that is often viewed as anything but is a tension that is central to her output. "You know, I had to have a lot of courage to do fashion," she said when we first met more than a decade ago. "In theory it is the least feminist work possible and at that time, in the late Seventies, that was very complicated for me."

As a young woman, Prada, who has a degree in political science and then studied mime with the Piccolo Teatro in Milan, was a signed-up member of the Communist Party and a reluctant inheritor of her grandfather's leather goods and glass company. She finally took the helm there in 1978.

"Italian society was becoming obsessed with consumerism, but my big dreams were of justice, equality and moral regeneration," she said. "I was a Communist but being left wing was fashionable then. I was no different from thousands of middle-class kids."

But in the 21st century it is fortuitous that Prada's exploration of sweetness is among the standout collections of the season. Next month an exhibition of her work opens at the Costume Institute of the Metropolitan Museum of Art in New York. The output of this vibrant fashion entity – Prada is among the great success stories of the past 25 years and its eponymous designer is influential to a degree that is unprecedented – will be displayed alongside that of the couturier, Elsa Schiaparelli, famed for her collaborations with the Surrealist art movement and with Salvador Dali in particular.

Like Prada herself, Schiaparelli was an inveterate risk taker and also born in Italy. The show, "Schiaparelli and Prada: Impossible Conversations" (the name comes from the Mexican artist Miguel Covarrubias' column, "Impossible Interviews", in Vanity Fair in the 1930s) aims to explore "the striking affinities between these two Italian designers from different eras".

"Given the role Surrealism and other art movements play in the designs of both Schiaparelli and Prada, it seems only fitting that their inventive creations be explored at the Met," Thomas P Campbell, that museum's director, says. "Schiaparelli's collaborations with Dali and Cocteau as well as Prada's Fondazione Prada push art and fashion ever closer, in a direct, synergistic and culturally redefining relationship."

In fact, while Schiaparelli actually created garments with fine artists – the 1937 white evening gown painted with a lobster by Dali is the most famous example – Prada tends to keep her position as patron and collector separate. She is taken seriously enough in that role to have introduced last year's Turner Prize, but actually employing an artist's work in the creation of a dress, say, is not on her agenda. More significantly, Prada's work, like Schiaparelli's – or Schiap, as she was always known – is far from mainstream or people- pleasing.

So different is the output of both creators from that of their contemporaries that it has in its time been branded "ugly" (as in belle laide); Schiaparelli's "hard chic", no-frills tailoring meanwhile could arguably be seen as a precursor to Prada's obsession with uniform, from her runway debut in 1988 and throughout the early 1990s. She was married to Prada CEO Patrizio Bertelli in 1987, wearing a less-than-conventionally pretty military-grey cotton dress and a man's overcoat.

In the end, Schiaparelli and Prada share a desire to break rules and question our notions of beauty. And that is the hallmark of visionary designers, male and female.

'Schiaparelli and Prada: Impossible Conversations' is at the Metropolitan Museum of Art from 10 May to 19 August 2012; metmuseum.org