Background: Internationally, many children and adults with intellectual disabilities are continually being supported by their family members to live within their family home. However, as a consequence of the ageing process some family members can struggle to continue to care because of their failing physical and/or mental ill‐health. This has resulted in a shift in the parameters of the relationship for some adults with intellectual disabilities with their formerly dependent role evolving into a caregiving one. This had become known as "reciprocity" or "mutual support." Limited information exists about these "hidden carers" and what services are available to support them. Aim: This article explored the lived experiences of nine adults with intellectual disabilities who provided emotional and tangible support to an ageing family member. Method: A qualitative methodology was employed using semi‐structured interviews. Nine participants with mild‐to‐moderate intellectual disabilities were interviewed within one region of the United Kingdom. The interviews were analyzed using thematic analysis. Findings: Five themes emerged within these narrative accounts: natural transition to caring; the health needs of the ageing family member; support; impact of caregiving and future planning. Discussion: The needs of these unknown hidden carers, and also ageing family members, are immediate and urgent. Policy makers, commissioners and service providers need to examine the type of "in‐house" support provided to these new carers if they are to continue living within their family home with their ageing family member, who will also need additional support. Neglecting both cohorts will lead to greater costs to services in the longer term and seriously threaten the quality of life of people with intellectual disabilities and their family carers.