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Kendall Jenner sure doesn't look like most 15-year-olds.

Clad in heavy makeup and skimpy hot pants, the aspiring model recently vogued for the cameras as the face of Marc Clark's new T-shirt line.

"I know I say it all the time, but I swear, she gets more and more professional with every shoot she does," half-sister Khloe Kardashian blogged Monday. "It just blows my mind that both she and Kylie have transformed from my baby sisters into these beautiful young women."

Khloe, 26, isn't the only family member floored by Kendall's grown-up photo shoot: Kim Kardashian also raved about Kendall -- who raised eyebrows after she posed in a skimpy string bikini over the summer -- by calling her a "true pro."

"I'm obsessed with these shots of Kendall," Kim, 30, gushed. "I swear she just gets more stunning with each photo shoot!"