The 17-year-old reality TV star, who previously claimed she used "six different colored" lip products to achieve her noticeably fuller pout, insists she never lied about having work done in the past, but concedes she "might have tiptoed around the truth."
In an upcoming clip from Keeping Up with the Kardashians the brunette beauty reveals: "I have temporary lip fillers, it's just an insecurity of mine and it's what I wanted to do."
Kylie, who is dating 25-year-old rapper Tyga, also claims she has felt under pressure to look good, but wanted to come clean about her lips for some time.
She says: "Everyone always picks us apart. I want to admit to the lips, but people are so quick to judge me on everything, so I might have tiptoed around the truth, but I didn't lie."
The teenager decided to come clean after her older half-sister Khloé Kardashian urged her to tell the truth.
In another clip, the 30-year-old star says: "Kylie decided to plump her lips and I don't think there is anything wrong with that. I think if you've done something though, it is right to cop up to it. If you avoid the question you're gonna look like a liar."
Kylie previously urged her fans not to copy her look after the #KylieJennerChallenge started trending on Twitter, prompting users to go to extreme lengths to mimic her full lips.
After photographs of fans with severely swollen lips began to flood the site, she tweeted: "I'm not here to try & encourage people/young girls to look like me or to think this is the way they should look.
"I want to encourage people/young girls like me to be YOURSELF & not be afraid to experiment w your look."