She added that the proposal took her completely by surprise.
"[Was I expecting it?] Absolutely not. He said to me, 'Miranda, I'm telling you now, this is the first and last time I'm going to kneel down in front of you,' she said.
"I was terribly nervous and emotional, trembling with happiness."
The pair announced their engagement earlier this year on social media, with Miranda posting a photo captioned, "I said yes!!!"
The couple first stepped out together in June 2015, and Kerr made her relationship Instagram official in March with these romantic vacation photos of the two in Washington, D.C.