It's the seemingly simple dress that's causing a huge stir in offices around the country, and appears to have broken the internet.
Possibly the most divisive question of the day is "What colour is it?"
Celebs have weighed in and scientists have also had their say.
An explanation why you see this dress as blue and black or white and gold. pic.twitter.com/ayXpqavC9B— Andy Rexford (@andyrexford) February 27, 2015
I don't understand this odd dress debate and I feel like it's a trick somehow. I'm confused and scared. PS it's OBVIOUSLY BLUE AND BLACK— Taylor Swift (@taylorswift13) February 27, 2015
The 'Great Dress Debate of 2015' has also inspired violent reactions from firm "Black and Blue" supporters.
It left some scratching their heads.
The color of a dress? Really? That's what you're asking Me? THE OCEAN LEVELS ROSE FOUR INCHES IN TWO YEARS. You know that, right?— God (@TheTweetOfGod) February 27, 2015
And others feeling victorious after apparently solving the mystery.
News break – February 27