Kylie Jenner's racy Instagram posts could be bothering Kim Kardashian. According to a report from Hollywood Life, the "Keeping Up with the Kardashians" star called out her underage sister for bragging about her body.

"Kim has told Kylie she better watch what she says about her body because it will come back to bite her in the a**!" an insider revealed.

"Kim told her that she used to be like Kylie, never working out and eating junk food but those days are over."

"Kim wants Kylie to know it takes hard work, exercise, diet and willpower to look as good as she does. Especially in her 30s after having a baby!" the insider explained about Kim Kardashian's disappointment over her sister seemingly being too cocky.

The report said Kim Kardashian's advice for the 17-year-old reality star came after she and her other siblings began getting annoyed at Kylie Jenner's attitude, evident in Instagram posts of her wearing very little clothing.

"Kylie takes it all for granted and it sometimes does grate on her sisters' nerves," the source revealed.

The TV personality regularly flaunts her slim physique via photos uploaded on Kylie Jenner's Instagram page. Most of the photos have been criticized for being too racy, showing her wearing skimpy swimwear, cleavage-bearing tops and very short bottoms.

Aside from Kylie Jenner's revealing Instagram photos, another reason why Kim Kardashian called out her underage sister is because of her interview with In Style UK.

In the feature, the youngest daughter of Kris Jenner and Bruce Jenner revealed that she has not worked out in the gym for more than two years.

"I haven't worked out in two and a half years," Kylie Jenner said.

"I'm living out my youth, not doing any exercise and eating what I want, which is pretty bad."

"I'm into yellow rice - you cook it for 15 minutes and it tastes so good," she added.