The 23-year-old British singer said that she chooses her stage outfits according to how comfortable they are, rather than how they make her look.
She told 'more magazine', 'I'm not very confident actually I've never been like that. That's just not the kind of person I am.
'I don't wear catsuits to be sexy. It's funny, people say to me, 'Your stuff is so sexual' but here I am in a long-sleeved catsuit covering everything.
'Fashion should be about what makes you comfy and I like dressing like a superhero.'
But she added that comfortable or not, fans can never expect to catch her in a girlie dress.
'I think it's fun to dress up with the earrings and lipstick and big shoes,' she said. 'I've always been someone who loves bold things.
'I could never go on stage in a pink frilly dress - that's not going to fit with my music or me.'