The present study investigated the effects on students' learning experience of adding a video of a teacher to an e-learning module. A total of 43 undergraduates were asked to learn the content of a pedagogical document either with or without a teacher video on the screen. Although video captures of teachers are increasingly being integrated into online courses, few studies have investigated their impact and the best way of optimizing them. According to the social-cue hypothesis, the presence of a teacher (face and gestures) positively influences learners' motivation and engagement in their learning. By contrast, the interference hypothesis holds that the teacher's presence can lead to poor performances, as it acts as a source of visual interference that diverts students' attention away from the relevant information. By assessing subjective ratings and learning outcomes, the present study tended to support the social-cue hypothesis, as it showed that adding a teacher video on screen significantly improved students' retention of the spoken explanations, without disturbing either their performances on diagram and transfer problems or the time needed to process the document. Eye-tracking data showed that students spent 25% of their time watching the teacher video. Adding this video had no significant observable effects on the subjective ratings (i.e., social presence, evaluation of the teacher's motivational skills, situational interest, cognitive load). These results suggest that videos of teachers can be used to improve social cues in multimedia learning without creating interference effects.