Kristen Stewart's traded in her signature laid-back style (including the Converse sneaks) for some glamorous looks while promoting The Twilight Saga's newest installment, Eclipse (in theaters June 30th). While her co-stars Anna Kendrick and Ashley Greene are dishing about their style plans for the movie's promotional tour, Stewart has already found her perfect red carpet formula: the LBD. At last night's Rome premiere, she looked stunning in a glamorous one-shouldered ruffled Marchesa dress and Roger Vivier platforms (left). During a photo call in Italy, Stewart opted for ladylike chic in a J. Mendel tweed and organza dress paired with peep toe pumps (right). But our personal favorite was the belted, long-sleeve Prabal Gurung minidress (center) she wore to the Korean premiere—it was the perfect mix of Stewart's trademark tough-girl style and newfound glam.