Kylie Jenner’s mature look has raised eyebrows over the past year, with many headlines focusing on the 17-year-old’s suspiciously plump pout. But she told fans and reporters alike—time and time again—that her large lips were just the product of some hard work and lip liner in front of her makeup mirror.

But the truth is: She had temporary lip fillers. And she needed her mother’s permission to do it.

According to the American Society of Plastic Surgeons’ website, any person under 18 needs parental consent to have a procedure done.

“As with any surgery, parental consent is required for all plastic surgery procedures performed on teens younger than 18 years old,” the site declares.

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A Beverly Hills plastic surgeon echoed that sentiment when he spoke to Perez Hilton about Jenner’s appearance last year.

“It is illegal to treat a minor without parental permission unless they are legally emancipated,” David Alessi told the gossip site.

A rep for the Jenner family did not return FOX411’s request for comment regarding whether or not the teen had her momager’s permission to get the procedure done.

Meanwhile, Jenner’s admission confirms what many suspected, but the teen star had previously denied.

"I have temporary lip fillers, it's just an insecurity of mine and it's what I wanted to do," she is seen saying in an upcoming episode of “Keeping up with the Kardashians.” "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 never lie.”

The entire extended Kardashian family seemingly helped the youngest member of the Kardashian/Jenner brood hide her enhancement secret.

In a recent episode of the family reality show, Kourtney Kardashian’s boyfriend Scott Disick mused, "Have you seen [Kylie Jenner] do her lipstick? It takes like 40 minutes.”

Meanwhile, her older sister Kim Kardashian once said in an interview, "I go into her room and I'm like, 'What liner do you wear?' because she only wears lip-liner and then she fills it in.”

The 17-year-old defended her changing look when speaking to Cosmopolitan.

"You guys have watched me grow up since I was 9,” she said back in February. “My face is going to get different. Now, I know how to do my makeup, contour and everything. I'm not against surgery. I'd never say no, but I don't desire it right now."

Jenner’s claims led to a trend of teens trying to pump up their pouts to look like Jenner’s—and they didn’t just run to the story to buy lip liner. Several weeks ago, Jenner fans took to social media to spread the #KylieJennerChallenge.

For the viral trend, fans put their mouths into a glass and sucked, causing swollen and bruised lips.

“You’re creating an injury to your lips, that’s why they swell,” Dr. Scot Glasberg, president of the American Society of Plastic Surgeons (ASPS), told FoxNews.com at the time. “It’s like punching yourself in the face or running your face into the wall.”

At the time, Jenner 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."

The members of the Kardashian and Jenner family have yet to tweet about Kylie Jenner’s admission.