While her sisters Kim, Kourtney and Khloe Kardashian are busy filming their reality show and promoting their Kardashian Kollection for Sears clothing line, younger sis Kendall Jenner is tearing it up in the modeling world.

The 15-year-old, who signed with Wilhelmina Models at the age of 13, makes her debut as the face of Australian swimwear brand White Sands in these just-released photos from their Spring/Summer 2012 ad campaign.

PHOTOS: Kendall and the Kardashians vacation in Bora Bora

Back in August, big sis Kim, 30, shared a behind-the-scenes photo from Jenner's White Sands shoot, exclaiming, "How stunning does she look!?!? I couldn't be more proud!"

VIDEO: Kim pushes Kendall into modeling

This isn't the first time Jenner has stripped down for a photo shoot -- she posed in Forever 21 swimwear ads in 2010 at the age of 14.

VIDEO: Bruce Jenner defends his daughter's racy bikini shots

Just last month, the slim-bodied teen hit the catwalk during Mercedes-Benz Fashion Week in NYC, where she strutted her stuff on the Sherri Hill Spring 2012 runway.

"OMGGGG just finished my first ever runway show for @sherrihill!!! #amazing #imaddictedtorunway!" the Keeping Up with the Kardashians star tweeted on September 14.

Tell Us: What do you think of Jenner's swimwear ads?

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