Sorry, folks, show's over - THAT dress IS blue and black: As millions join raging debate over color of mother of the bride's outfit we track down the real thing and settle it once and for all

• Colours of two-tone dress have become a topic of debate on social media
• Some viewers see the bodycon dress as white with gold lace detailing
• Others see royal blue with black while a few insist the colours change
• It became internet sensation and was tweeted by stars like Kim Kardashian
• She sees white and gold, while husband Kanye West sees black and blue 
• #TheDress started trending worldwide on Twitter as discussion went global
• Dress, made by Roman Originals, appears to actually be black and blue
• Picture was first posted on Tumblr by Caitlin McNeill, 21, from Scotland 
• Uploaded it after noticing friends saw different colours in the photograph 

It is the question that has divided the internet: is this dress white and gold, or blue and black? 

The two-toned frock has sparked a fierce online debate, with users taking to social media to argue over what colours they see.

The picture of the dress was first posted on Tumblr by Caitlin McNeill, a 21-year-old aspiring singer from Scotland, after noticing her friends saw different colours in the photograph. 

The image has become an online sensation, with posts arguing over the dress's original colours - and science behind the debate - being viewed and shared millions of times.

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True colours: This photograph of Cecelia Bleasdale in 'the dress', left, with daughter Grace Johnston and son-in-law Keir Johnston, reveals that the frock is royal blue with a black lace trim

Internet sensation: This picture of the dress has sparked debate, with viewers disagreeing over the colour

Black and blue: The real colours of the dress, made by British clothing company Roman Originals

Find out the truth: Roman Originals on THAT dress

Even celebrities weighed in on the fashion debate, with Kim Kardashian asking her 29.4million Twitter followers to help settle a disagreement between herself and husband Kanye West. 

REVEALING ITS TRUE COLOURS: SCIENCE BEHIND THE DRESS 

By Victoria Woollaston for MailOnline

Andrew Lotery, Professor of Ophthalmology in the Faculty of Medicine at the University of Southampton, told MailOnline that the difference in perception could be due to lighting conditions, the device the image is being viewed on and even a person’s age and gender.

He explained that everyone has different combinations of the genes that create the sense of colour for red, green and blue and because these genes are on the X chromosome, women tend to have more variations.

As a result, women have a more dynamic range of colour so may be more susceptible and sensitive to specific colours. This may explain why women flip between seeing the different colours, and men typically don’t.

He added that some people have more than one ‘dose’ of a blue colour gene, as an example, so they will see higher or lower levels of this colour, too.

Additionally, as people get older their perception of colour changes.

The lens of the eye gradually yellows with age and this exposes more blue, continued Professor Lotery.

This will influence how deep or strong a colour appears and could explain why older people may see the blues and blacks rather than the whites and golds.

He gave the example that painters such as Monet and Rembrandt painted scenes when they were younger that were predominantly one colour, but the same scenes featured more red when painted later in life.

Elsewhere, Professor Lotery said: ‘The occipital lobe is responsible for actually processing the vision and there may be an element of optical illusion to [the photo of the dress].’

Many work by contrasting images and colours, and this contrast could explain the differences seen on the dress.

‘It’s quite a striking contrast between the black and the blue’ continued Professor Lotery.

‘For example, it could be that if the lighting conditions slightly changed, the person viewing the image is getting more stimulus on the blue photo receptor, for example, than the red.

‘On the balance of stimulating one a subtle change in angle could make it flip. This includes the type of room, the monitor, the lighting and so on.

Plus, if your brain is focusing specifically on the differences your vision may be on the cusp of colour recognition and this could cause the differences.’

Other conditions, such as the development of cataracts, changes the way people see the colour blue, and that could play a role too. 

And #TheDress started trending worldwide on Twitter as the debate when global. At 3.15pm this afternoon, there had been more than 1 million tweets mentioning the hashtag.

The photograph that started the internet storm was taken by Cecilia Bleasdale while she was deciding on what to wear to her daughter's upcoming wedding.

Ms Bleasdale sent the picture of the frock to her daughter, Grace , to ask the bride-to-be what she thought. Grace, in turn, shared it with her then-fiance, Kier Johnston.

The couple disagreed over the colours of the dress, which can be purchased here, and Grace sought more opinions online. 

The bride-to-be then posted the picture on Facebook, and her friends continued to debate the colour of the dress.  

The debate was forgotten until Caitlin McNeill, a close friend of the newlyweds, posted the picture on Tumblr days after the wedding, which took place on Saturday on the Scottish island of Colonsay.

Ms McNeill, whose folk band played at the ceremony, shared the photograph on a fan page dedicated to talent manager Sarah Weichel.

Weichel, who represents YouTube stars, told Business Insider last night that her phone began blowing up on Thursday after McNeill's post started going viral. 

'The crazy thing is, I actually have nothing to do with the post,' she said. 'But I have been getting a ton of phone calls and emails tonight.'

The page gave the dress the exposure that sent it into the online stratosphere.

It was quickly picked up by bloggers, news outlets and Twitter users, who have spent the last 24 hours commenting on the dress - and the debate it has spared. 

Speaking to Business Insider, Ms McNeill, said she couldn't believe the way the dress has exploded online.

She said: 'I thought my followers on Tumblr would maybe have a good reaction, but I never would have considered that Taylor Swift and Mindy Kaling would be tweeting about it.' 

Meanwhile, as the newlyweds enjoy their honeymoon in Jamaica, their friends and families have been shocked by the coverage over the dress.

Mr Johnston's mother, Shirley Johnston, 62, said the reaction had been 'really weird' while 26-year-old Lindsay Maden, from Blackpool, who was a bridesmaid at the wedding, described it as 'mental'. 

The bride's sister, Angie McPhee, 27, said that she thought the newly-married couple were unaware of the social media storm. 

She said: 'I think Grace is going to wake up in Jamaica and think oh my god, what is going on.'

Commenting on how the dress looked on her mother, Miss McPhee said: 'Fabulous. She looked absolutely fabulous on the day.'

Millions have since joined the raging debate - dubbed 'dressgate' - with a number of high-profile celebrities among those who have weighed in on the issue.

Actress Mindy Kaling also joined the discussion, writing on Twitter: 'IT'S A BLUE AND BLACK DRESS! ARE YOU F***ING KIDDING ME'. 

Her friend and fellow actor BJ Novak replied writing, 'white and gold.' 

Creating a buzz: Kim Kardashian called on her 29.4million Twitter followers to help settle a disagreement

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Star power: Celebrities including Mindy Kaling, B.J. Novak and Oscar-winner Julianne Moore join the debate

'Confused and scared': Taylor Swift told her Twitter followers that the dress is 'obviously blue and black'

Joining in: Justin Bieber was one of the last celebrities to chime with his views on the dress on Twitter 

Then recent Oscar winner Julianne Moore jumped in, writing to Novak and Kaling; 'what's the matter with u guys, it's white and gold.' 

To that, Novak replied to Moore; 'Thank you!And congratulations on your Oscar, which Mindy thinks is purple and green.'  

Taylor Swift wrote; '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.' 

And Justin Bieber kept his fans happy by telling them that he sees 'blue and black'.

McNeill said that she never expected the post to prompt such a star-studded debate. 

Some celebrities avoided the issue completely, simply declaring that the dress was ugly. 

Model Chrissy Teigen told her 655,000 Twitter followers: 'F*** the dress it's heinous. While Oscar-winner Jared Leto branded it 'fugly'. 

McNeill said she never expected the picture to spark a star-studded debate, explaining that she just thought her followers on Tumblr would have a 'good reaction'.