The 36-year-old socialite confirmed Tuesday to People that she said "yes" to the 32-year-old actor while on a ski trip in Aspen, Colo., over the weekend.
"I am so excited to be engaged to the love of my life and my best friend," she told the magazine.
"I have never felt so happy, safe and loved. He is perfect for me in every way and showed me that fairytales really do exist!"
Hilton said she and Zylka were posing for a photo on the slopes when the actor got down on one knee and popped the question.
"The ring was so gorgeous and sparkling. I was shaking as I put it on. It is the most beautiful ring that I have ever seen!" she gushed.
Hilton also shared the news in an Instagram post Tuesday. She posted a slideshow of pictures from Zylka's proposal, including a snapshot of her massive diamond ring.
"I said Yas!" the star wrote.
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"So happy & excited to be engaged to the love of my life. My best friend & soulmate. Perfect for me in every way. So dedicated, loyal, loving & kindhearted. I feel like the luckiest girl in the world! You are my dream come true."
Hilton and Zylka first met at an Oscars party eight years ago, and went public with their romance in February.
The actor is known for playing Jake Armstrong on "The Secret Circle" and Tom Garvey on "The Leftovers."
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