Much lip service has been paid to whether Kylie Jenner's much fuller pout is courtesy of injections or some very impressive makeup skills, as she's repeatedly claimed.

Jenner really wanted to hang on to the idea that her new lips could have been created using a lot of lip liner , but her fib gets busted by her own sister, Khloe Kardashian , on this week's episode of "Keeping Up with the Kardashians."

In a new preview clip, Jenner is shocked after reporters start asking her about her lips at an event. The camera then cuts to Khloe's confessional, in which she lays out the truth bomb we've been waiting for.

"Kylie decided to plump her lips. I dont think theres anything wrong with that. I think if youve done something though, it is right to cop up to it," she says.

That's not in the cards for Jenner who tells her sister, "Im not ever going to deny or confirm anything."

Of course, the 17-year-old reality star would go on to firmly deny having plastic surgery in a recent interview with Grazia magazine. "I haven't had plastic surgery. I've never been under the knife. People flashback to pictures of me when I was 12 and say 'Kylie's so different,' but how can I look the same from 12 to 18?'" Jenner clearly chose her words carefully, considering lip injections don't require going "under the knife."