Marshall cast Heather Matarazzo as Mia's best friend Lilly Moscovitz after casting director Marcia Ross introduced them to each other, insisting that Matarazzo is different from other actresses. Matarazzo attended a chemistry reading with Hathaway after auditioning for Marshall; Hathaway believes that the two actresses had met each other several times prior, none of which Matarazzo remembers, expounding, "I was such a sarcastic, little punk-ass kid that couldn't be bothered by cheerfulness" while "She's such a warmhearted, beautiful, sweet, soulful woman". Matarazzo insists that they got along well despite their differences, likening their on-screen chemistry to Richard Gere and Roberts' in "Pretty Woman". Furthermore, the actress cites Marshall as her favourite director, whose positive energy she described as unrivaled by other directors. Matarazzo was also starstruck by the opportunity to work with Andrews, whose films she had idolized as a child, and often asked for the actress' autograph.