The bra, often worn as a top, is the first unmissable trend at Milan Fashion Week, seen Tuesday at Prada and on Wednesday at Fendi — off in the distance through mirrored glass.

Maria Grazia Chiuri was in a mood for lingerie, flirty slipdresses, filmy dance dresses, racy animal prints and lace rompers, adding a sensual pulse to the Roman-based brand — along with a disco beat.

Hits by Raffaella Carrà, who was pinned on Chiari’s mood board this season, heightened the ’70s feeling of the collection, as did head scarves, fringed bags, dangling fur tippets and folkloric vests.

Guests at the show first alighted on a line from an E.E. Cummings poem, lit up like a theater marquee: “I like my body when it is with your body.”

Strange then to separate the collection from the audience, which kept hoping these flowing, filmy clothes might whisk by them more clearly, allowing fuller appreciation of all the sumptuous fabrics and techniques listed in the press notes, including silks, intarsias and embroideries. Instead they had to squint past reflections of themselves.

(In the release, the brand said the set was inspired by Italian artist Luciano Fabro’s “Mirror Cube.”)

Despite all those distractions, it was plain that Chiuri loosened up a little for her second Fendi ready-to-wear show, explaining over a mic before the show that the house’s roots in fur were a springboard for the languid, gossamer silhouettes for spring.

Fur was “not only a material” for the founding Fendi sisters, but “something that is also close to the idea of lightness, sensuality — and very close also with the body, too,” she explained. “For me, Fendi is about this lightness.”

During her briefing, Chiuri was also adamant that her new focus on the body, and the materials that reveal and conceal it, was something of a reaction to the state of the industry: “I understand that now fashion apparently is only about brand,” she said dryly.

And so she hacked away at the white tuxedo shirts seen in her first show, reducing one to a sexy harness top. She also carved out portholes on the sides of clinging dresses, and gave plunging necklines to her skimpy lace dresses.

Once again, the runway was dominated by black, which is clearly still a go-to color for Chiuri, but perhaps overly serious for a brand whose FF logo, designed by Karl Lagerfeld in 1965, stands for “Fun Fur.”

Now that she’s brought sexy back, and some disco energy, could fun be far behind?