In recent years, the growing number of individuals facing mental health challenges is placing an unprecedented strain on our healthcare services to facilitate adequate care. At the same time, Artificial Intelligence (AI) has increasingly been used as a supplement for triaging, diagnosis and treatment recommendations both in public and private healthcare settings. Our project is an international collaboration between the University of Southampton in the UK and the Institute for Experiential AI at Northeastern University (USA), aiming to lead the conversation on how AI can be used responsibly in mental health care. We bring together experts from mental health, computer science, ethics, and policy, along with voices from industry, the third sector, and public sector, with the goal to create guidelines that ensure user protection, privacy, and fairness. These guidelines will help in applying AI responsibly within health services, potentially easing the burden on healthcare providers and enhancing patient care. We are keen to engage with stakeholders from all sectors – from public agencies to private industry – to gather insights and shape these guidelines effectively.