A source close to the two tells ET that they broke up and called off their engagement a few weeks ago. The source adds that the relationship moved too fast, and Hilton realized over time that Zylka wasn't the one for her, and their relationship just wasn't meant to be.
Hilton also seemingly confirmed the split on her own via Instagram on Monday, captioning a video of herself "Miss Independent."
Hilton, 37, and Zylka, 33, started dating over two years ago, after they connected at Art Basel in Miami, Florida. The actor proposed to Hilton in January during their ski trip to Aspen, Colorado, with a massive, pear-shaped sparkler worth $2 million.
"I am so excited to be engaged to the love of my life and my best friend," Hilton tweeted at the time. "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!"
Before their split, Hilton and Zylka had nothing but amazing things to say about each other during recent interviews with ET.
"I feel like I'm glowing and just feel... I don't know, just like a woman," Hilton gushed in March, while speaking to ET at the iHeartRadio Awards. "Just like an adult. Like, I don't know. I feel like my life is finally just starting."
"I think she's one of the most intellectual women I've ever met, just taking advice from her in every aspect," Zylka added. "I think the better question is what don't you like [about her] and there's nothing."
Hilton also confirmed to ET in June that she had already picked out a wedding dress and selected some of the members of her bridal party. She was planning to have her sister, Nicky Hilton, stand by her side as maid of honor.
Hear's more on Hilton and Zylka in happier times in the video below.