After years of thin, heavily arched and over-drawn brows, the trend is swinging to the opposite: straight brows, a clean and natural shape that, stylists say, suits almost every face. It's not a revolution - it's a return to what is the most natural shape for most people anyway.

The idea comes from Korean beauty culture, where straight brows have long symbolised youth, softness and naturalness. Unlike the heavily arched kind, which can harden the expression, a straight line gives harmony and visual balance - the face looks fresher and more rested, without a single intervention you can see.

Achieving it doesn't take much, but it takes measure. Stylists recommend a consultation to fit the shape to the structure of the face, rather than blindly copying someone else's. The technique is subtle: soften the arch a little, maintain it with occasional tweezing and an anti-thinning serum, and finish with a tinted gel that fixes without over-defining.

The list of those already wearing this shape is long - from Sara Sampaio and Zoe Kravitz to Dua Lipa and Emma Stone. When so many faces from the front rows pick the "undone" look at the same time, it's almost never an accident; behind every bit of "naturalness" on the red carpet there's usually a team and a few hours of work.

And here's the small irony of the whole story. The ideal effect is the "this is just how I woke up" look - carefully shaped, but never artificial. In other words, the industry now sells the effort of looking like you made no effort. Which is, come to think of it, the most expensive naturalness money can buy.