Kourtney Kardashian and Kendall Jenner may be the hottest in their family, but they have something else in common.

That something is threatening to tear the two of them apart with jealousy.

And his name is Luka Sabbat.

A source revealed to InTouch Weekly magazine that Kendall and Kourtney are in konflict.

“It’s all because of Kourtney’s latest boy toy,” the insider announces.

“Luka<‘ the source shares. “Was into Kendall first.”

(Well, so were a lot of people)

The insider explains that this is something “which Kourtney knew, but she just swooped right in anyway.”

Kendall Jenner and Luka Sabbat

“That’s caused some serious jealousy issues between the sisters,” the source explains.

Sometimes friends or loved ones are happy to share a guy, but the Kardashians and Jenners are a little too traditional for that.

In the insider’s view, Kendall and Luka are a “way better match” than Kourtney and Luka.

There are a lot of reasons for that — the lesser age difference, the fact that both are models, the fact that Kourt is a mom.

The source predicts that “Kourtney will move on from Luka in no time.”

Kourtney’s rumored boy toy is only 20 years old.

In contrast, Kourtney herself is just months away from turning 40.

We’re not saying that Kourtney is “too old.”

If they really are dating, this is just two consenting adults doing consensual adult things.

But you can imagine that some are surprised to see a mother-of-three dating a guy who isn’t old enough to drink.

It’s a little weird. And maybe it’s a little creepy.

That said, if you’re going to date a woman twice your age who is also a mother … you might as well date a mega-MILF, right?

Kourtney may just be dating Luka for fun, or to one-up (well, match) Scott Disick’s 20-year-old model girlfriend, Sofia Richie.

If so, maybe they both will move on soon.

If and when that happens, if Luka needs a shoulder (or other body part) to cry on, well, 23-year-old Kendall is age-appropriate and will probably be available.

We have to admit that we’re unsure of this narrative.

Now, if Kourtney really did swoop in and snatch up Luka in her talons just as Kendall was leaning in for a kiss, sure.

But this would hardly be the first time that sisters in that family had experienced the other’s sloppy seconds.

In fact, before Travis Scott impregnated Kylie last year, he had banged Kendall.

He even made headlines for publicly comparing and contrasting the two sisters on how they are in bed.

(Ugh, don’t get us started on how creepy that was)

Obviously, the sisterly bond should be indelible.

The Kardashians are all about “the power of family,” after all.

We hope that Kendall and Kourtney are too close to be torn apart by the same guy.

In the mean time, high five to them both for having great taste. Luka’s one handsome dude.

And with the other hand, high five to Luka for attracting the interest of not one but two of the most beautiful women on the planet.