Experienced teachers are often perceived as skillful performers of improvisational activities in the classroom. The student teacher has a narrower basis for carrying out the activity with the same level and quality of improvisation due to the lack of experience and repertoire. A key question is: Does the student teacher improvise at all? Furthermore, how can this improvisational activity be described? This study aims at describing improvisational teacher knowledge and skills. The study uses principles from an exercise within improvisational theater performance. Furthermore, the study examines how student teachers and experienced teachers use teacher knowledge and skills in project based practice. The practice is an area where student creativity is fostered to a larger degree. The study attempts to explain how student teachers and experienced teachers apply this individually, but also in relation to each other. The research questions are as follows: 1. How can one describe improvisational teacher knowledge and skills in music pedagogic practice? 2. How do teachers and student teachers use improvisational teacher knowledge and skills in project-organized practice? Findings show that experienced teachers use structures and frameworks effectively to create an open space where the pupil in guidance with the teacher, are given the opportunity to discuss curricular goals and conceptual comprehension. The teacher applies different approaches and examples to progress the conversation, so that the students can develop their own ideas in a creative process. The dialogue is open for student input, and the teacher progress the conversation based on the student input. By doing this, the teacher can control the conversation through an open dialogue guide. On the other hand, the student teacher lacks both experience and repertoire to teach with the same level of flexibility and structures as the experienced teacher. A more one-way4 conversation dominates the way the student teacher teaches. Generally, it is observed that the student teacher controls the conversation with a closed dialogue guide, because the conversation does to a much lesser degree allow for input and adaptive development. The student teacher does, however, show tendencies towards an open dialogue guide but stalling at an early phase of the conversation. The discussion suggests that the teacher education needs to incorporate the term ¨improvisation¨, viewed as an effective teaching activity, towards conceptual knowledge. The term improvisation, and improvisation as an activity, should be a subject that is both discussed and exercised in practice.