Want to try the trend? Katie Wright asked a hair expert everything you need to know.

Selena Gomez is – without a doubt – a fashion and beauty icon. As the most followed person on Instagram (136 million followers and counting), the singer’s every hair, make-up and fashion choice are pored over endlessly, but she wasn’t famous for being edgy – until now.

Earlier this week, the 25-year-old unveiled a punky new haircut; her long brunette locks pulled up into a high plaited ponytail to reveal a shaved section at the nape of her neck.

‘Always need a subtle change’ the American star wrote alongside the photo, which has already racked up nearly 4.5 million likes.

Celebrity hairstylist Marissa Marino shared the same photo, writing ‘My girl #selenagomez at it again…she loves to keep me on my toes! Thanks @timduenashair for making her undercut dreams come true!’

Marino also tagged the picture #newtrendalert, anticipating that the star’s fans will want to get in on the undercut action too – and when it looks this good, why wouldn’t they?

"I think Selena’s undercut looks really cool, especially the way they’ve styled the hair tight and sleek in the high-plaited ponytail," says hairstylist Tom Connell from Trevor Sorbie.

"The angle of the jaw and cheekbone follows on to the angle of the ponytail and the angle of the undercut, so it works seamlessly. I think she describes it as ‘subtle’ ironically, and is playing it down and being cool."

But before you grab the clippers or head to the salon, there are a few things to think about, like your hair type and whether you’re prepared for the upkeep of an undercut.

Here’s Connell’s advice if you’re thinking about going for the chop…

Undercuts were traditionally done to take the weight out of thick hair – does that mean people with fine hair shouldn’t have one?
"It doesn’t necessarily mean that, and yes, people with fine hair can have an undercut – it all depends on how you cut it and how the hair is going to fall. It needs to be the right amount of hair with the right weight distribution.

"My recommendation would be to go to a very experienced hairdresser to ensure it’s cut properly."

What do you need to consider before getting an undercut?
"It’s mainly the day-to-day and why you’re getting an undercut you should consider, so how you’ll be wearing your hair, as this then affects the angle of the undercut.

"Sometimes, if people do get one to remove weight, the undercut will be cut where the bulkiest part of the hair is. So this may not be in the same place as Selena’s.

For example, if you have a bob cut and have a lot of thickness behind the ears, you’d maybe consider an undercut behind the ears.

"Is it an aesthetic thing or is it practical? These are the questions you need to ask and speak to your hairdresser about."

Is an undercut tricky in terms of maintenance – how often will it need to be trimmed to maintain the look?
"It is, yes, you’ll need to get it trimmed often to keep it neat and sharp, or it can start to look scruffy.

"This will depend on your hair type, but it may be similar to going in for a fringe trim in between hair appointments – you may need to go in and get your undercut trimmed."

What happens when you want to grow out an undercut, is an awkward in-between phase inevitable?
"When you have an undercut, you’re cutting the hair all the same length. So, when it grows back, it will grow at the same rate and you’ll end up with a weighty, thick block of hair.

"You will need your hairdresser to regularly trim the undercut, to take out the weight, so the hair grows down and not out."