has revealed the secret behind half-sisterKylie 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."
"She's so good at make-up," added Kim. "Every event she does it herself
." Kyliesparked 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. TheKeeping up with the Kardashians
star soon spoke out to share her frustration. "I feel like everyone has been talking about it for months," she toldE! News
. "I'm kind of sick of it
. My pictures, I palp them out a lot. I think big lips are awesome."
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 wasspotted 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.