The 19-year-old singer admitted that she feels self-conscious about her body, but insisted that she would never go too far with cosmetic surgery.
"I don't have any boobs so I feel a bit self-conscious. I'd do anything to have Jesy's curves, she's got the most incredible body," she told The Sun.
"I used to think I might have a boob job, but I'm waiting because I'm only 19. If I ever did get it done I wouldn't go massive, just bigger to suit my shape."
Speaking of her relationship with Sam Craske, she added: "I think we are all good girlfriends, we don't care about looking stupid. I'm more like a mate with Sam. I don't feel sexy at all, the idea of it makes me cringe."
Thirlwall was apparently threatened by a man at Wireless Festival last month, who said he was going to stab her.
Watch Little Mix's video for 'Wings' below: