A new online body trend has been apparently sweeping the internet.

Basically, it's a brand new reason to hate yourself, and follows trends like thigh gaps and thighbrows.

Now the ab crack has arrived on the scene.

It involves a groove in your ab muscles creating a crack down below your chest, and seems to involve quite a lot of core work.

Reacting, one tweeter says it sounds like one more thing that collects sweat, and another wonders if builder's arse crack counts, as he hasn't seen the real thing.