"It just kind of happened at Christmas," she said.
Cruz, 34, is keeping quiet about her husband-to-be, but revealed that he's English and from London.
"Cultural differences - they are definitely vast in some ways," the Cuban actress said.
With wedding plans now in motion, Cruz is already thinking about starting a family.
"I definitely want at least one because I would love to have the experience of giving birth, and I then I would like to maybe adopt some others," she said.
Cruz' ABC series Off the Map premieres Wednesday at 10/9c.