This study investigates the impact of ChatGPT on design students' creativity and their approach to the ideation process. Based on Glăveanu’s 5A's creativity framework, the research focuses on how the use of ChatGPT influences creative actors, actions and artifacts, as well as it’s affordance regarding critical appraisal. A mixed-methods approach was employed, combining quantitative analysis of design concepts and survey data with thematic analysis to gather qualitative insights from interviews and open-ended questions. Thirty-five design students participated in a within-group experiment, generating ideas under two conditions: with and without ChatGPT assistance. The findings reveal that while ChatGPT fosters quick generation of ideas, it can also reduce creative confidence and engagement, potentially narrowing exploration of the creative space. The study highlights a need for balanced integration of AI in creative workflows, offering recommendations for educators, practitioners, and tool developers to enhance the use of ChatGPT within ideation without undermining human creativity. Limitations and future directions for research are also discussed.