Starbucks is not the only chain to have a supposedly secret menu, and the latest secret drink to be revealed is the ‘ombre rainbow drink’.

The drinks recently went viral, largely due to their beautiful, colourful appearance and Instagram-ability, not to mention the fact that they tap into every millennial woman’s favourite obsession: ‘unicorn’ (read pastel rainbow) themed everything.

However, baristas are refusing to make the drinks because they claim the ombre concoctions require too much effort.

The ombre drinks are created by blending Starbucks’ previously secret colourful juice drinks (creatively titled the 'Pink Drink,' 'Purple Drink,' 'Orange Drink,' and 'Blue Drink').

And Starbucks’ lovers are going wild for the new rainbow blends - whether that’s for the taste or just the appearance is unclear.

But the coffee chain’s staff are not happy.

The baristas say the ombre drinks are too time-consuming to make, and given queues in Starbucks are already often long, the secret drinks would likely exacerbate the problem.

In a Reddit forum for Starbucks employees, baristas have been sharing their fury at the prospect of the drinks.

“I freaking refuse. No. Absolutely not. No way,” said one.

“If anyone legitimately orders one of those you can bet your ass I’m going to make sure the colours don’t mix so they don’t look as good on Instagram,” added another.

The ombre drinks were first revealed by food blogger Joe Castro who posted a picture of the drinks on his Instagram account.

But the baristas pointed out that the images of the drinks on Instagram had been filtered, and they remarked that you could tell by the vibrancy of the green straws.

“You can tell that pic is photoshopped into oblivion. I have seen the drinks in real life and they are nowhere near that vibrant (or tasty),” explained one.

Some baristas said they’d charge the customer for two drinks too.