The Sports Illustrated beauty was first linked to the reality Tv star in June (13), when they were spotted enjoying a meal together in New York City, but both denied reports suggesting they were an item.
But now Chmerkovskiy has finally confirmed the speculation, insisting that they never anticipated their friendship to take a romantic turn.
He tells Us Weekly, "She's an amazing person. 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 (sic)."
Upton has previously been linked to baseball star Justin Verlander and Sean 'Diddy' Combs, while Chmerkovskiy was previously engaged to fellow Dancing With the Stars pro Karina Smirnoff. He split from fellow dancer Peta Murgatroyd in February (13).