Credit: Brian Prahl/MM Splash News Online

After tying the knot Aug. 20 in Montecito, Calif. Kim Kardashian and Kris Humphries didn't just get a room -- they got a $3,300-a-night chalet on Italy's Amalfi Coast!

NBA hunk Humphries, 26, surprised his new bride, 30, with a last-minute escape to the five-star Hotel Santa Caterina, where, after arriving Aug. 23, they quickly put a"do not disturb" sign on the door of their ultra-luxe Romeo and Juliet suite.

As exclusive Us Weekly photos reveal, the newlyweds took full advantage of their private R&R time to catch up, swim in their private infinity pool, sunbathe and enjoy one another's company -- in barely-there swimsuits, naturally.

Says an onlooker: "They were giggling and splashing like kids!"

"Our honeymoon was so perfect! We caught up on alone time," Kardashian told Us after the sexy honeymoon.

Indeed, the hotel witness tells Us: "They only had eyes for each other...They were in their own little world."