According to the socialite's friend and publicist Jonathan Cheban - who the basketball star confided in when he was planning the proposal - the brunette beauty thought she had returned home to an empty house and was stunned by the scene in front of her when she went upstairs to change her clothes.
He said: "She walked upstairs and [Kris] was standing there holding flowers, 'Will you marry me?' [spelled out] in rose petals, on his knee. And it was crazy, because she would have sat downstairs for three hours while he sat there on one knee!
"We both know it's very hard to surprise Kim. It was amazing afterwards, she was so excited. but it was touch and go whether the surprise was going to get blown."
Jonathan revealed he convinced Kris - who plays for NBA side New Jersey Nets - to pop the question when the pair were back from their holiday, rather than do it "in front of a million people".
He told E! News he advised: "Do it on your own pace and not on a rushed vacation."
The pair have only been together for six months, but Jonathan said they are very happy together.
He added: "They love each other. They're [both] ear-to-ear smiles, which is great for us, all her friends. This is amazing. Everybody's really, really happy."