updated 01/19/2009 AT 01:00 AM EST
•originally published 01/19/2009 AT 01:00 AM EST
Actually, Smirnoff confesses, the big moment was not only memorable but comical. Chmerkovskiy, known for his macho persona on DWTS, lost all swagger when he presented Smirnoff with a three-carat Harry Winston square-cut-diamond-and-platinum engagement ring tucked inside a Louis Vuitton bag. "He got so nervous. He had difficulty forming sentences, which was so cute," Smirnoff says, giggling.
The pair—who have not set a wedding date—have known each other for 14 years as competitive ballroom dancers living in the New York City area. But after other relationships—including Smirnoff's high-profile romance with former DWTS celeb partner Mario Lopez—ended, the old friends began feeling more than platonic toward each other. In September, while having a casual dinner together, "we started talking and looking at each other completely differently," Smirnoff says. Adds Chmerkovskiy: "I'm not really sure how it happened, but it makes sense. I'm in love and so is she." Even the whirlwind courtship hasn't caused the couple to miss a step. "It's all good," says Chmerkovskiy. "Everything is beautiful."