She has appeared on the cover of several international fashion magazines, such as Germany's "Cosmopolitan" and "Glamour"; Spain's "Elle", "Telva" and "Harper's Bazaar"; UK's "Esquire" and "Love" and US' "V", "Porter", "Interview", "Ocean Drive", "Shape", "Allure", "Marie Claire" and "i-D". Valletta has walked in fashion shows for Versace, Lanvin, Louis Vuitton, Balenciaga, Gucci, Valentino, Prada, Michael Kors, Alberta Ferretti, Claude Montana, Dolce & Gabbana, Pierre Balmain, Sonia Rykiel, Versus, Yohji Yamamoto, Anna Molinari, Calvin Klein, Christian Dior and Tom Ford. She was the face of NARS Cosmetics' Spring 2010 Collection.