The field of TESOL has focused on how interest-driven practices (e.g., playing English-medium online games) facilitate incidental language and literacy development among language learners. Researchers have tried to bring students' interest-driven practices into formal language classrooms. This presentation shares the presenter's design-based research study on using popular pop culture content (TV shows) in her adult international English language learners in the U.S.. The presenter triangulated the three key elements - the learning potential of the target content, students' actual interest in the target content, and teacher's familiarity with the target content. Through the lens of affinity space (e.g., Gee, 2007) and L2 willingness to communicate (e.g., MacIntyre, et al., 1998), the qualitative analysis revealed how the course 1) evoked the feeling of fannishness' among the students to be more willing to communicate in English and 2) functioned as an affinity space that invited and enriched students' out-of-classroom interest-driven language practices.