Did Kylie Jenner get a boob job? After telling Cosmopolitan she hasn't had plastic surgery, she sparked rumors she got breast implants when she posted a very curvy photo on Instagram. Sporting a low-cut, cleavage-baring tank top, Kylie wrote: "@joycebonelli Secret Projects." Though Kylie's intention was to promote new projects she's working on, she got attention for a totally different reason.

UPDATE: New Photos Spark Rumors That Kylie Got Implants

Though many Kardashian fans thought Kylie looked amazing, critics worry that Kendall's 17-year-old sister is growing up way too fast. “Has boob injections too tho! @kyliejenner,” one person commented on her Instagram post with other asking, “How the f--ck?”

Kylie Jenner With Her Sisters Looking at Kylie Jenner with Khloe, Kim, Kourtney and Kendall at the 2011 People's Choice Awards she barely looks recognizable.

But Kylie has consistently denied plastic surgery and lip injections. “You guys have watched me grow up since I was 9. My face is going to get different. Now, I know how to do my makeup, contour and everything,” the Keeping Up With The Kardashians star said. “I’m not against surgery. I’d never say no, but I don’t desire it right now.”

RELATED: Kylie Jenner Denies Plastic Surgery

For some reason, though, Kylie's critics refuse to believe that her face and body could have changed naturally. Most 17-year-olds look different than they did at 12. Padded push-up bras also make a difference!

Kylie Jenner Sexy Instagram Photo Kylie Jenner looked super sexy in this Instagram picture from a commercial set. And before and after photos show just how much she has changed over the past year or so. She is relying on her big lips and hair extension line to help her stand out from her older sisters.

The question remains, though: Why is Kylie even posting a cleavage photo at 17? Sources say Kylie is obsessed with looking like Kim, who has gotten so much attention over the years. 

It doesn't help matters that Kim, Kourtney and Kendall all got attention in 2014 from nude or topless covers. From Kim's Paper magazine pictures to Kendall's racy Love photo shoot, the Kardashians and Jenners got attention last year from baring all. Not from covering up.

Kylie Jenner Denies Plastic Surgery Rumors Kylie Jenner was noticeably smaller on top when she hit the MTV Movie Awards in April 2013.

“[Kris] is constantly saying how beautiful Kendall is and doesn’t say the same thing about Kylie,” a source revealed. “Kris has always encouraged plastic surgery [and] has told Kylie how procedures like fillers and lip pumpers can make a huge difference.” Another source added that “Kylie is absolutely acting out she tries to get attention by dressing provocatively. It’s textbook.”

Even Bruce Jenner is concerned. He feels that Kris is sending the wrong message to all her kids — especially Kylie. “For the longest time, Bruce kept the divorce amicable,” a source said. “But now that it’s finalized, he’s ready to stop stepping back. It’s killing him to watch her look the other way as [Kylie and her sister Kendall] date older guys and make one bad decision after another.”