10102929Holly Health Prevent: Developing Precision Health Behaviour Change Product, using JITAI Coaching for MultimorbidityClosedCollaborative R&DInnovate UK30% of UK adults have multimorbidity (the presence of two or more long-term health conditions) and multimorbidity treatment and support accounts for 70% of total NHS health and social care expenditure. Notably, 34% of adults with multimorbidity have both physical and mental conditions (NICE, 2023), a combination that severely impacts people's ability to self-manage. 'Supported Self-Management', aimed at increasing patient action and health literacy, has been consistently shown to reduce/reverse disease progression and health service usage. However, despite evidenced benefits, there is a critical shortfall in NHS self-management support resulting from rising service demand, financial pressures, existing in-person Primary Care delivery model and training gaps. The proposed project will achieve this through significant progression of the proven Holly Health Personalised Digital Coaching Service (which itself has been found to result in an 18% increase in exercise, 22% increase in personal wellbeing and 33% people reducing their need for GP support), through the development of machine learning approaches, combined with emerging techniques in adaptive behaviour change support, to provide the right type of coaching interventions to the user at the right time, and dedicated to managing the complex challenge of multimorbidity. The new Holly Health Prevent app will provide a game changing advancement on existing digital personalised behavioural interventions and general health/wellness apps. Indeed, it will represent the first application of this kind in the management of multiple chronic conditions, with an initial focus on patients aged 40-65 who are at risk, and those who are already living with multimorbidity, with the aim of reducing onset and improving positive behavioural health outcomes. The project consortium harnesses Holly Health's proven track record of successfully bringing comparable products to market, Loughborough University's behavioural science expertise, and the primary healthcare and community services experience and patient access of the award-winning Modality Partnership. With Innovate UK support, the proposed 18-month project will enable innovation development to commence and finish at least 2 years sooner than without public funding. With the aim of becoming the go-to multimorbidity digital self-management tool, at a price point that supports access and scalability, the project has the potential to achieve positive health outcomes for hundreds of thousands of patients -- meeting clear current and future NHS and societal needs.