Model Liziane Gutierrez Gets Kim K.'s Ass in Surgery!

Kim Kardashian's famous ass just got jacked by Liziane Gutierrez ... who paid top dollar to get it.

The Brazilian model dropped $25,000 to go under the knife last month in her home country and pump up her booty. We're told she received injections of hyaluronic acid, which doesn't show up on X-rays ... critical to the booty community, apparently.

Liziane came out of the hour-long procedure with 39" hips. She's hoping her new digits -- 36-26-39 -- can win Brazil's famed Miss BumBum contest later this year.

Let the games begin!