17-year-old Kylie's admission came a few days back after weeks of ceaseless rumours of her having lip injections.
Kim, 34, said contrary to people's perception that Kylie lied for long about her super plump pout, her half-sister started using the fillers only recently, reported E! Online.
"I am," Kanye West's wife replied when asked if she's proud of her sister.
"But I think that, you'll see on the show, is that for a long time, Kylie really was over-lining her lips. And people thought at that time that she had done something, and she really didn't.