The British singer, who is dating One Direction's Zayn Malik, has never been able to sniff tasty foods or even her own perfume, and it is thought she suffers from a rare medical condition called congenital anosmia.
She tells the Bbc's Newsbeat, "I have never smelt anything, but I think I smelt coffee once. When people go, 'Ah she's cooking a Sunday roast', I'm like, how do you know that? I'm like, this is amazing, it's like magic.
"People are always like, 'Oh, isn't that really horrible?' and I'm like no because I've never known what it's like to smell. If I'd had it and then it disappeared I'd be like, 'Argh!' I wear the same perfume all the time, because everyone says, 'Oh you smell nice' and then I'm like, 'Ah, Ok.'"