This paper presents an instructional model to incorporate English-language communication between international practicing scientists and English learners into secondary science lessons. The aim was to identify a method that lets pupils practice English as the language of science and that elicits positive affective attitudes in the form of task-specific intrinsic motivation. As a central condition, the approach had to be feasible in realistic school settings. The pupils that participated in the two studies presented (total n = 218) were native German speakers and interacted with English-speaking experts in the curricular contexts of cytology and immunology via videos. We assessed pupils' task-specific intrinsic motivation (as defined by their "interest/enjoyment" of the exchange and their "relatedness" to the expert) and compared it to their subject-specific interest in biology and English before and after the project. We further contrasted the motivational ratings of bilingually experienced and inexperienced groups of pupils. Both groups reported similar and remarkably high task-specific intrinsic motivation for the video exchange. Subject-specific interests remained constant before and after implementing the method and were correlated with "interest/enjoyment" in the standard, but not in the bilingually experienced classes. The applicability of the exchange model in different topics, subjects, and student groups is discussed.