A new population of fibro/adipogenic progenitors (FAPs) is identified in skeletal muscle, which can differentiate into adipocytes and support myogenic differentiation. These cells are quiescent in healthy muscle but become active upon injury, proliferating and providing signals that enhance myogenic differentiation. FAPs do not generate myofibres but promote the differentiation of primary myogenic progenitors. In healthy muscle, FAPs do not engraft or differentiate into adipocytes, but in damaged muscle, they do so, suggesting that the environment controls their behavior. FAPs are distinct from myogenic progenitors and arise from a separate developmental lineage. They are abundant in healthy muscle and rapidly enter the cell cycle upon injury. FAPs contribute to muscle regeneration by providing a transient environment that enhances myogenic differentiation. The study highlights the role of FAPs in muscle healing and regeneration, emphasizing the importance of multiple cell types in the process. The findings suggest that FAPs are a key component in the physiological context of muscle regeneration, and their study may lead to therapeutic strategies for reducing fibrosis in chronic diseases.A new population of fibro/adipogenic progenitors (FAPs) is identified in skeletal muscle, which can differentiate into adipocytes and support myogenic differentiation. These cells are quiescent in healthy muscle but become active upon injury, proliferating and providing signals that enhance myogenic differentiation. FAPs do not generate myofibres but promote the differentiation of primary myogenic progenitors. In healthy muscle, FAPs do not engraft or differentiate into adipocytes, but in damaged muscle, they do so, suggesting that the environment controls their behavior. FAPs are distinct from myogenic progenitors and arise from a separate developmental lineage. They are abundant in healthy muscle and rapidly enter the cell cycle upon injury. FAPs contribute to muscle regeneration by providing a transient environment that enhances myogenic differentiation. The study highlights the role of FAPs in muscle healing and regeneration, emphasizing the importance of multiple cell types in the process. The findings suggest that FAPs are a key component in the physiological context of muscle regeneration, and their study may lead to therapeutic strategies for reducing fibrosis in chronic diseases.