Specular highlights, though valuable for human perception, are often undesirable in computer vision and graphics tasks as they can obscure surface details and affect analysis. Existing methods rely on multi-stage pipelines or multi-label datasets, making training difficult. In this study, we propose a one-step diffusion-based model for specular highlight removal, leveraging a pre-trained diffusion-based image generation model with an adaptation mechanism to enhance efficiency and adaptability. To further improve the adaptation process, we introduce ProbLoRA, a novel modification of Low-Rank Adaptation (LoRA), designed to adapt the diffusion model for highlight removal effectively. Our approach surpasses existing methods, achieving state-of-the-art performance in both quantitative metrics and visual quality. Extensive experiments on synthetic and real-world datasets demonstrate the effectiveness of our method, highlighting its robustness and generalization capabilities.