Star Fashion

Savannah had a convenient muse in sister Sienna while studying at Central St. Martin's design school. "I had always used Sienna as my fit model," Savannah told WWD. "She would also always give advice on how things should look. She's always had this great sense of style."

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Silk dress, $181.90; at saksfifthavenue.com.
Cropped jacket, $279; at intermixonline.com.