Kate Upton's boyfriend never expected to fall in love with her.

Former 'Dancing With the Stars' professional Maksim Chmerkovskiy has opened up about his relationship with the Sports Illustrated model for the first time, and says she is an ''amazing person''.

The 33-year-old dancer told UsMagazine.com: ''We have an incredible time together, and, you know, I definitely didn't see that coming and I think neither did she.''

The couple got together after being introduced by mutual friends more than six months ago.

He added: ''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.''

Maksim's younger brother Val Chmerkovskiy, 27, also gets on well with Kate.

He said: ''I think she's awesome. She's a great girl, and we're great friends. She's an incredible chick and we have a great time.''

An insider previously revealed that Maksim originally feared the 21-year-old blonde beauty was too young for him.

The source said: ''(He was) hesitant to start things with Upton because she was so young. They have a lot of fun. She's very mature for 21.''