What colour do you see this dress as - Blue & Black or White & Gold?
There is a huge debate happening about the colour of this dress.
It's blue and black! No, it's white and gold!
Even in the Magic Freebies office we've been arguing for at least half an hour.
What do you see?
The garment was first seen on Tumblr, posted up by a blogger whose friends couldn't agree on the colours - white and gold or blue and black.
Celebrities from Kim Kardashian to Taylor Swift have taken to Twitter to say what they can see.
So what's actually going on?
It's all about the light.
The helpful folks at wired.com have found Bevil Conway, a neuroscientist who studies colour and vision. It turns out that daylight, and how we have evolved is changing the colour you see in the dress.
'What’s happening here is your visual system is looking at this thing, and you’re trying to discount the chromatic bias of the daylight axis.'
In simple terms - it's completely up to your brain and eyes, as to what you see. People either discount the blue side, which means you see white and gold - or you discount the gold side, which means you see blue and black.