"She's an amazing person," Chmerkovskiy told Us Weekly. "We have an incredible time together, and, you know, I definitely didn't see that coming and I think neither did she. We enjoy each other's company very much and like I said, she's a great girl that I never thought anything romantic like this could have happened."
Chmerkovskiy, 33, and Upton, 21, were first rumored to be dating back in June. They've since been spotted holding hands but have never confirmed the relationship until now.
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"I think she's awesome," Chmerkovskiy 's brother Val added. "She's a great girl, and we're great friends. She's an incredible chick and we have a great time."
Chmerkovskiy was previously engaged to fellow Dancing with the Starspro Karina Smirnoff.
What do you think of the pairing?