This article uses the concept of ‘mediation’ to account for the sociomateriality involved in the rehearsal of a new play. Drawing on ideas from the ‘New Sociology of Art’ that has its origins in Science and Technology Studies, we show how the sociomateriality of the rehearsal is an essential part of the process of theatre-making. It means giving to materials, bodies and matters in the rehearsal room a crucial role in the process of developing and refining a scene. Using ethnographic research methods, with particular emphasis on excerpts from video recordings, we analyse specific activities that take place in the rehearsal room to give a less anthropocentric and a more nuanced reading of the processes that contribute to the creation of a scene. Analysing the dynamics of entanglements in work practices of performance-making, we reveal the material base of the easily overlooked professional processes that constitute the craft of theatre.