Fashion is in the throes of revisiting all things 1990s, from grunge (see Dries Van Noten’s jewelled flannel shirts, Junya Watanabe’s denims and Vivienne Westwood’s artfully frayed knits) to the ubiquitous platform trainers (Giuseppe Zanotti, Marc by Marc Jacobs and Christian Louboutin). So perhaps it’s no surprise that the underwear-as-outerwear trend is back. This time, however, it is less about what you see, and more about what you don’t.

Maria Williams, head of lingerie buying at Net-a-Porter, says: “What we’re seeing is a breaking down of boundaries between ready-to-wear and intimates. Ultimately, it’s a trend that is about bringing the focus back to the woman’s body.”

It’s an attitude echoed by design duo Domenico Dolce and Stefano Gabbana. “Lingerie is the maximum expression of a woman’s femininity,” says Gabbana. “Instead of covering a woman’s body, we prefer to accentuate its qualities.”

Sarah Shotton, creative director at lingerie retailer Agent Provocateur, says: “People increasingly want to subtly show off their lingerie and we are designing pieces to let them do that. But it’s not showing up for work in a pencil skirt and a bra; it’s about giving a hint of something.”

See, for example the bestselling bras at Agent Provocateur: Annoushka (£160), a halter-neck-style in delicate lace; the Jet (£110), which criss-crosses the décolletage; and the tulle and silk Demelza (£125). Prim and proper they are not, but each bra is designed to give just a hint of what lies beneath when fully clothed.

At the spring/summer 2014 collections shown in Paris in October, Stella McCartney mixed her crisp suiting with sensuous lace-trimmed slip dresses and camisoles. She wasn’t the only one to mix innerwear and outerwear. There were bra-tops at Prada, Isabel Marant and Dolce & Gabbana, an endless parade of see-through lace at Burberry; fishnet bodystockings worn by melancholy Vegas showgirls at Louis Vuitton; big underwear-revealing skirts at Giambattista Valli; and layers upon layers of sheer everywhere from Balenciaga to Calvin Klein Collection.

The trend has even crossed over to the high street. “Outerwear and lingerie will intertwine further next season,” says Soozie Jenkinson, head of lingerie design at Marks and Spencer. “Clothing trends on the catwalks for spring will demand a variety of lingerie solutions.” This, she says, ranges from “look at me” items such as longline bralets and camisoles to skin-tone pieces designed to do a disappearing act under sheer fabric.

Of course, sex and fashion have never been strangers. But it would seem that these old bedfellows are in the process of renegotiating their relationship – perhaps as a result of the debate about hyper-sexualisation in popular culture, from Kate Moss’s Playboy shoot to Miley Cyrus’s twerking, Lily Allen’s flesh-baring music video parody, Terry Richardson’s sexualised brand of fashion photography, or the 50 Shades of Grey phenomenon. Even worthy artistic types have discovered a newfound reverence for, or at least fascination with, pornography. The work of Italian erotic film director Tinto Brass was celebrated in a documentary at the 2013 Venice Film Festival. Lars von Trier’s latest film, Nymphomaniac , is touted as an art house film with graphic unsimulated sex scenes, and boasts an all-star cast including Charlotte Gainsbourg, Shia LaBeouf, and Uma Thurman.

Shotton says: “I think, with the likes of Miley Cyrus, things have got very extreme and that’s not necessarily sexy. I prefer to leave a little to the imagination”.