Among the more than 200 pieces that make up the V&A's latest blockbuster exhibition, Undressed: A Brief History of Underwear, is a thong, still in its packaging, made by Rudi Gernreich from 1978. Gernnreich was the man credited with giving that barely-there bit of fabric its name, and this example of a "golden nude", we are told, is a rare find. And given the recent news that sales of thongs – or g-strings, whatever you like to call them – are in decline , this rarity may quickly turn into relic.Okay, that might be jumping the gun slightly – dedicated thong-wearers still walk among us, and probably always will. But it's a good example of what an exhibition such as this can reveal about our sartorial habits. The surprising thing is, however, just how little the contents of our knicker drawers have changed over time.Arranged thematically across a number of sections – Fashion, Health and Hygiene; Volume; Performance Underwear and Support: Bras and Girdles – the exhibition shows us 19th-century corsets next to 21st-century waist trainers, bustles next to butt lifts, and bust extenders next to push-up bras. The fabrics and technology used might have progressed, but the purpose of these pieces has pretty much remained the same."We scorn corsets and we're horrified by layers of petticoats, but actually we haven't evolved all that much," says the exhibition's research assistant, Susanna Cordner. "While underwear since the 18th century has really changed, the reasons we wear it haven't changed at all. It's for hygiene, comfort, acts as a barrier and provides support or creates a silhouette. Now we just use different methods, different moulds and different materials to express those different functions."Indeed, people were flashing their garters long before they were showing off the waistbands of their Calvin Kleins. And while we might have coined a new term – "athleisure" – for Beyonce's much-hyped Ivy Park range, performance-wear is nothing new – you only need to look to the specially-made corsets for lady cyclists for proof.2016 is a proving to be a big year for our smalls. Aside from the V&A's exhibition – the largest survey of its kind ever – Selfridges is endeavouring to revolutionise the way we shop for our undies with its newly-opened Body Studio . The largest launch in the department store's history, the Body Studio is bringing together lingerie, fitness and wellbeing (yes, there's even a Hemsley and Hemsley cafe) all in one 37,000 sq ft space to put the female form centre stage.If, like me, you're used to bulk-buying pants from M&S, replenishing the stock only when the last pair has almost disintegrated, and haven't been fitted for a bra since, well, ever... then a visit to the Body Studio – with its hundred-odd brands to choose from and bra fitting service – could prove to be a life changing experience."The Body Studio has completely re-imagined a forgotten, overlooked corner of a store," says Buying Manager Heather Gramston. "It's an almost-immersive experience which is about celebrating and embracing the body and creating a place where women can feel good."But what are we filling our drawers with right now? "There's been a return to logo or gender neutral underwear, but also to lace," says Cordner. "Whichever camp you fall in, it's about framing the body rather than adorning or sculpting it. There's been a change in bust shape too, and now we're going for more of a teardrop-shape rather than a really propelled bust."Gramston agrees: "Women are wanting a natural shape, almost a 70s look, which lends itself to mesh fabrics. It's not necessarily completely soft cup, but something that looks and feels natural when worn underneath clothes."Fashion's marriage to underwear is long and enduring. Whether it's underwear as outwear – one of the most iconic examples of this trend, Kate Moss' translucent slip dress and black pants ensemble, is on show at the V&A – or ready-to-wear influencing what it is we put on under our clothes, one is reflective of the other.