The Oscar-winning actress took to Instagram over the weekend to show off her latest surprise beauty move, the undercut tattoo. And in doing so, she joined the ranks of those pioneering the hottest hair trend of the moment.

Undercut tattoos involve shaving short a portion of hair from the nape of the neck upwards, then precision shaving in delicate patterns. These motifs can range from geometric designs to intricate floral symbols, but one thing is certain -- they are taking over social media.

Berry has opted for the latter, with her online snap showing off a lotus design that peters down into the base of her neck. The rest of her hair is piled up into a bun on the top of her head, showcasing her light golden highlights.

This is one of the main advantages of the undercut tattoo -- it is edgy and individual, but you don't have to put it on show full-time. No one will be any the wiser when your hair is left loose, but on hot summer evenings you'll get to feel the benefit of the breeze on your neck.

Undercut tattoos have been around for some time, but as Berry's snap proves, they are becoming increasingly mainstream. Type in the hashtags #undercutgirls and #undercutdesign on Instagram and the site throws up thousands of pictures of women showing off their take on the trend. Some go super minimalist, opting for a standard undercut with shapes cut into the hairline, while others go for skulls, third eyes, and the aforementioned floral designs. The best part, of course, is that it will usually grow out in a matter of weeks, so if you tend to get bored of your hairstyle easily, this could be the tattoo for you.