"I just hope I don't throw up or cry from nerves," she tells USA Today.
Hart, who will hit the floor with Mark Ballas, says she has a bit of experience: she and her husband, musician Mark Wilkerson, choreographed a "flashy, fancy and super fun" routine to "Never Tear Us Apart" by INXS for their wedding.
She also taught her son Mason, 3, the 69 Boyz' "Tootsee Roll," she tells the paper.
But that doesn't necessarily translate to winning that trophy disco ball.
"People keep saying, 'Don't do it unless you're going to win,'" Hart says. "It all depends on what I'm able to pull off and what the other competition is like."
She's already stacked up who she's against.
"I think Donny [Osmond] is the most popular of the group, for sure. And I think he's going to get the popular vote," she says. "I just hope he can't dance very well. He can't drive very well -- I beat him in a race a couple years ago, so we'll see if I can duplicate that."
As for musicians, "I think Mya is going to be a big contender, definitely," she says. "She looks like she's got the moves and obviously she knows music so she's got rhythm. Aaron Carter, same thing."
She says "you never know" about the athletes.
"My husband's really worried about Michael Irvin -- wide receivers take ballet," she says. "And the Olympians, they're the ones that have the endurance and they've already got the muscle, the strength, form and coaching. They're used to that rigorous schedule."
She can't wait to meet one competitor in particular: snowboarder Louis Vito.
"I've snowboarded for 17 years and I'm hoping that when this is all over he'll show me some moves on a half-pipe," she says. "But he's able to do things with his body -- jump in the air and twist around and whatnot -- so who knows what he's going to be able to pull off on the dance floor."