What colour is this dress? The question has divided the nation!

If you're looking to exercise some brainpower this morning, we have a little test for you.

Tumblr user Swiked posted this picture of a dress yesterday and asked users if they could tell whether the real colours of the fabric were blue and black or white and gold. "Guys please help me – is this dress white and gold, or blue and black? Me and my friends can’t agree and we are freaking the f**k out," the user wrote.

The question soon resulted in worldwide, internet-breaking panic.

Some people are INSISTING it's blue and black, while others are certain it's white and gold.

What do you see?

Even celebrities got in on the argument, with Taylor Swift and Mindy Kaling firmly planted in the Blue/Black camp:

However Julianne Moore, Sarah Hyland, Kim Kardashian, and even Ireland's own Mairead Farrell and Anton Savage are all rooting for White and Gold:

What is happening?! 

Experts have said that the differing perception of colour is due to some people's eyes compensating for bad lighting by making the colours appear as white and gold.

One smart Tumblr user found the dress on Google, and we have to say, it looks fairly blue and black IRL!

Could this be the weirdest debate of all time?!