Late on Thursday night and early Friday morning, Twitter and Facebook feeds across the world had only one question on their mind: Is this dress white and gold or is it black and blue.

The dress in question. The original image is in the middle. At left, is the image, which shows the dress as white and gold and the one on the extreme right shows it as blue and black

The dress, made by clothing company Roman Originals, is in fact black and blue.

The science behind the reason why some people see black on blue while others see gold on white is that the picture is an optical illusion.