Jack Osbourne's fiancee Lisa Stelly is months away from giving birth, but his sister Kelly has already begun scouring baby boutiques for the latest designer fashions.

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"I already told him that this baby, whether it's a boy or a girl, is going to be the best-dressed baby there is," Kelly 26, told Us Weekly at Macy's Material Girl Search in New York City Wednesday. "'You're not buying the clothes -- I am!'"

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Kelly, who said she's "very, very excited" to become an aunt, certainly knows a thing or two about fashion: she was in the Big Apple to find the next Material Girl spokesmodel with Madonna's 15-year-old daughter, Lourdes Leon.

"This is not just a model position," Kelly explained. "You are a spokesperson and you have to do appearances, so you have to be a good public speaker and have confidence in who you are."

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The E! Fashion Police critic added that their ideal spokesmodel must "love anything with fashion" and be a sartorial risk taker -- "just an all around true Material Girl."

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