Perhaps Paris Hilton's taking a page out of her frenemy Kim Kardashian's push-up bra book?

The heiress — who's arguably responsible for Kimmy's fame (along with Ray J) — stepped out in London on Tuesday night and nearly busted out of her gray sweater dress!

With her fur vest wide open in 40-degree weather, Paris' boobs looked like they were trying to escape for some air.

And by the looks of that guy's face in the background, the back of that ensemble was just as visually stimulating as the front.

That's hot…we guess.

Scroll through to see the other ladies in Hollywood who love a good push-up bra!