Is Scott Disick getting between Kourtney and Khloe Kardashian?

By most accounts, Kourtney and Khloe Kardashian have a tight sisterly bond. But there might be a little one-sided jealousy simmering below the surface.

Radar Online reports that Kourtney, 35, has been struck by the green-eyed monster over 30-year-old Khloe's hot new body…and her appreciative partner Scott Disick, 32, isn't helping.

In fact, a source says that earlier this month when Kourtney posted "Today's Mission: To try and get my butt looking like Khloe Kardashian's" on Instagram, there was a bit of jealousy mixed in with her admiration.

"Scott is always complimenting Khloe on her boobs and her butt and it is really starting to get to Kourtney," the insider says.

"Now that Khloe has a hot body and she is getting all this attention, Kourtney feels like she has to catch up and has upped her workout in the hopes of getting the same results as her sister."

Scott is further fuelling Kourtney's insecurity by constantly pointing out how hot the mum of three used to be. Whoa! Is he blind? Has he not seen those recent Instagram pics?

And there's also the deep bond that Khloe and Scott share. At one point, rumours were even floating around that they'd hooked up.

"Khloe and Scott have this weird bond that Kourtney and him don't have and it has always been that way," the source adds.

"They are like bros. Whenever s**t is going down between Scott and Kourtney, Khloe is the first one that he turns to and that automatically puts her in the middle of their relationship. It just gets old."

Here's a tense moment between the sisters on KUWTK ​that has nothing to do with Scott.