November 20, 2014 - 14:40 GMT hellomagazine.com Kim Kardashian has revealed the truth about half sister Kylie Jenner's lips. Kim Kardashian has revealed the secret behind half-sister Kylie Jenner's full lips. The 33-year-old admitted that her younger sibling's plump, big lips are down to Kylie's enviable make-up and beauty skills. "She draws her lip, and it looks amazing," she told beauty blog Pixiwoo. "I go into her room like, 'What liner do you wear' because she only wears a lip liner and she fills it in, she doesn't wear a lipstick or a lip gloss." Kim Kardashian has revealed that Kylie's plump lips are down to make-up "She's so good at make-up," added Kim. "Every event she does it herself." Kylie sparked speculation that she had undergone cosmetic treatment on her lips after fans noticed that they seemed bigger and fuller in her Instagram photos compared to older images from the year before. The Keeping up with the Kardashians star soon spoke out to share her frustration. "I feel like everyone has been talking about it for months," she told E! News. "I'm kind of sick of it. My pictures, I palp them out a lot. I think big lips are awesome." Kylie Jenner sparked speculation that she had cosmetic treatment with her Instagram photos The young fashionista also took to Twitter to ask fans to stop speculating. "How long are we gonna talk about this lip thing lmao," she wrote. However, the 17-year-old was spotted stepping out of her car earlier this week going make-up free, with fans quickly noting that her lips were back to their original shape, prompting them to suggest that it is indeed down to Kylie's make-up skills.