Kendall donned a white frock with a keyhole cut-out and cape while Kylie opted for mini black shorts and a long-sleeved ivory blouse. Both girls paired their ensembles with nude heels.
But it looks like their fans, who have watched the starlets grow up since the E! reality show got its start in 2007, aren't the only ones who are surprised at Kylie and Kendall's recent transformations.
"Kendall is the new face of Australian swimwear designer Leah Madden's Summer 2012 campaign Pirouette!!,"' Kim revealed on her website August 1. She added: "How stunning does she look!?!? I couldn't be more proud!"
Tell Us: Do you think Kylie and Kendall look age-appropriate or way too mature?