The rapid advancement of artificial intelligence (AI) is transforming education and creating new opportunities for language learning and teaching. In English as a Foreign Language (EFL) contexts, idiomatic competence represents a persistent instructional challenge because it requires cultural awareness and contextual understanding. Traditional approaches often overlook these essential dimensions, limiting learners' ability to comprehend and use idiomatic expressions effectively. This article examines how ChatGPT, an AI-powered tool, can address this gap by serving as a digital assistant in EFL instruction. Through interactive and context-driven activities such as context-creating prompts, gap-fill exercises, and AI-generated visuals, ChatGPT fosters idiomatic comprehension in ways that engage learners dynamically. The discussion underscores the importance of teacher oversight to ensure linguistic accuracy, pedagogical soundness, and cultural appropriateness. Ethical considerations, including AI bias and the risk of over-reliance on automated tools, also receive careful attention. The article concludes that, when integrated with discernment, ChatGPT notably enhances EFL instruction by supporting the development of idiomatic competence in culturally informed, intellectually engaging, and dynamic ways.