The ballroom beauty is engaged to Brad Penny, 32, she told PEOPLE on Saturday, revealing the couple has actually been engaged since Oct. 4!
"We kept it quiet because my family is in New York and Brad's family is in Oklahoma so we kind of wanted them to come out and celebrate and be a family first before we let the cat out of the bag," she said.
Smirnoff, 32, showed off her 4.5 carat Asscher Cut diamond engagement ring at Tao Las Vegas's five-year anniversary party.
The two have yet to start planning the wedding. The proposal, however, took some scheming. Smirnoff calls it "a conspiracy" between Penny and Smirnoff's manager, who told Smirnoff that the president of Twitter wanted to meet her after a taping of Dancing With the Stars.
"We went to this restaurant and [my manager] got on her phone and said 'this guy is killing me,' and got up and walked away, Then Brad walked in and it still didn't register. He got down on one knee and he opened the box and I said, 'Thank you'. I honestly didn't expect it."
Though Penny, who played baseball last year for the St. Louis Cardinals, wasn't at Tao with his fiancé, he sent her a hand-written note in a fortune cookie apologizing for his absence – the cookie also contained an Everlon diamond necklace.
"I'm marrying a Southern Gentleman," she said.
The couple began dating in October 2009, shortly after Smirnoff and fellow Dancing With The Stars pro Maksim Chmerkovskiy called off their engagement.
Smirnoff and Penny met through a mutual friend, UFC fighter Chuck Liddell.