Kylie Jenner & Stassie Karanikolaou might have unimpressed expressions on their faces, but they’re actually bursting with excitement … or, at least, nearly busting out of their tops!

Jenner shared several pics with her longtime pal Saturday … showing the two sitting side by side in a car with tight white tank tops, leaving little to the imagination!

Check out the pics … the two dark-haired vixens are pulling out all their modeling experience for this hot impromptu photo shoot — pouty lips and serious expressions galore.

Stassie does break into a grin at one point, showing off her sparkling pearly whites … though Kylie’s intent on keeping her composure in the photo.

Kylie captured the photos, “🤍♾️” … to which Stassie replied in the comments, “our song 🥹🥹🫶🏼🫶🏼🫶🏼.” We don’t fully get the meaning — but, that’s just what happens when you hear two besties talking to one another!

Kylie’s all about barely-there tops these days, it seems … remember, we shared video yesterday of Jenner’s boobs stealing the show during a makeup tutorial — though she went on the other end of the color spectrum for that busty look.