But according to a friend of the former couple, reports of a breakup are actually "a little over the top."
"It was never really that serious," the source says, characterizing Kate and Maks' relationship as "more like friends-with-benefits than anything else."
A rep for Upton had no comment.
"Things actually fizzled out between them in September," the insider adds. "Maks moved to L.A. for his acting career and Kate relocated to NYC. After that, they actually didn't see very much of each other. There's no hard feelings, I'm sure they'll remain friendly."