The 22-year-old star, who is famed for her slender figure and outlandish sense of style, is worried the fashion industry is indoctrinating women with an unhealthy attitude towards body image by only using super-skinny girls on the catwalk.
And the "Umbrella" hitmaker is adamant youngsters should never try to copy their idols because it is not "possible" to maintain such a tiny frame.
She tells Britain's You magazine, "You shouldn't be pressured into trying to be thin by the fashion industry, because they only want models that are like human mannequins. They know that if we see an outfit on a mannequin in a shop window we will love it and want to buy it whatever size we are. That's why they have size zero models - they want to sell clothes.