Brief backstory: This is Kylie Jenner.

And these are her lips.

Some people have wondered if Kylie Jenner's lips are fake.
Others believed she was just overlining her lips.
Well, the mystery is finally solved. In a new clip from an upcoming episode of Keeping Up With the Kardashians, Khloé Kardashian admits that Kylie "plumped" her lips.
View this video on YouTube
For those of you who don't know, "plumping" means Kylie got injections into her lips.
The clip starts out with Kylie being nervous about a journalist's persisting questions.
Then Khloé comes in with the drop:
Khloé then gives Kylie some big sister advice...
But Kylie is all, "Long hair, don't care."
In another clip, Kylie fully admits her lips are injected with fillers.