In research on communication in music lessons, masterclasses, and rehearsals, there is a growing focus on multimodal interaction using conversation analysis (CA), where the combination of talk and embodied actions (e.g., using musical instruments, gestures, voice, and score) provides the opportunity to study this complex area in microscopic detail and the potential for findings to inform practice. A methodological approach informed by CA was used to explore processes in peer-led musical theatre rehearsals in a university, where students adopted the roles of both musical director and performer. The data consisted of 12 hr of video-recordings of rehearsals that took place over the course of 5 weeks and involved 24 participants; the data were analyzed to identify patterns in relation to informal interruptions (talking that did not relate to the task at hand) that occurred during the rehearsals, and how they were managed by the student director so that rehearsing could be resumed. Management often involved musical prompting as part of a three-stage sequence: (1) orienting to the piano, (2) giving directives, and (3) initiating performance. The directors’ prompts included vocalizing, playing the piano accompaniment, and making bodily movements. These actions served to capture the performers’ attention, interrupt the informal talk, bring the focus back to performing, and indicate performers’ starting notes. The director completed the sequence by initiating a run-through of the previously rehearsed segment of the performance. The findings not only have implications for students’ management of rehearsals but also highlight the value of studying multimodal rehearsal interactions and techniques generally to ensure effective and efficient delivery in typically time-constrained rehearsal periods.