The former Dancing With The Stars pro admitted in an interview with Glamour that her competitive streak can get "silly" at times.
"Ryan and I are very alike," she said. "When we work out with a trainer, we'll die before we stop, like to the point where we can't breathe."
Hough, who revealed that Seacrest is "always joking" about the 13-year gap in their ages, added that she was partly drawn to the American Idol host's competitive side.
"I think it's that similarity I was talking about before [which attracted me to him]," she said. "We both like that perfection in ourselves, and we want to make our relationship like that."
Hough, who stars in the upcoming movie Rock Of Ages, recently signed up to appear alongside Josh Duhamel in the Nicholas Sparks adaptation Safe Haven.