The present study aimed at investigating the effectiveness of using  a suggested hybrid instructional model, based on task-based and challenge-based language learning approaches, in developing third-year English majors' creative writing skills and creative  self-efficacy. The study followd a quasi-experimental approach using mixed methods of data collection; qualitative and quantitative. Accordingly, twenty-eight (28) English majors participated in the present study. To meet the objectives of the study, a creative writing skills test and a creative self-efficacy scale (Abbott, 2010) were used as quantitative instruments. In addition, semi-structured interviews were carried out as a qualitative instrument. Results of the study revealed the high effectiveness of the hybrid instructional model in developing creative writing skills (fluency, flexibility, originality and elaboration). It also helped in increasing the study group's creative self-efficacy. The qualitative analysis offered valuable insights into how the suggested model significantly impacted the particpants' engagement, language learning experience, creative writing skills and creative self-efficacy. The study recommended the use of the suggested hybrid model to develop English majors' creative writing skills and creative self-efficacy as well.