Rob Kardashian: I'm Over 200 Pounds, Want to Lose Weight on 'DWTS'

Who knew?

Rob Kardashian is fighting the battle of the bulge -- and he wants to change that through his just-announced stint on "Dancing With the Stars."

"I really want to get into shape," the reality star, 24, told Us Weekly Monday, after the Season 13 cast was revealed. (Kardashian joins celebs like Chaz Bono, Kristin Cavallari, Ricki Lake, Nancy Grace, Elisabetta Canalis, David Arquette and others for ABC's hit competition.)

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"You probably wouldn't know, but I'm the most insecure and overweight I've ever been," the "Keeping Up With the Kardashians" sibling confessed. "I'm over 200 pounds, so I want to drop weight and this will be a good start."

But Rob has a long road ahead of him in the dance department. "I'm not a confident dancer at all," he said. "And down the road ... I don't want to be that guy who doesn't dance at his own wedding!"

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Rob's most famous sibling, Kim, already had her "DWTS" moment. "She just said, like 'You're going to be really nervous.' [But] I don't want her advice -- I don't need advice from someone who lasted, I think three weeks."

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Kardashian had another motivator for doing the show: His mom-ager, Kris Jenner. "My mom pretty much forced me to do this show. She did it to Kim and now she's doing it to me! [She] just says, 'Smile and be yourself''"

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