Fruitful social interactions require constant monitoring of one's own and others’ actions. We previously showed that macaques playing a video game in a controlled laboratory setting are able to perform joint actions (JA) successfully, when asked to control moving visual cursors displayed on a screen. Yet, while error monitoring is fundamental to optimize motor dyadic performances, it remains unexplored whether macaques are aware of acting together in this abstract context. To fill this gap, we analyzed spontaneous task-unrelated head movements during dyadic performance to investigate their awareness of being engaged in a joint action task. Two monkeys sitting next to each other performed an isometric JA. Each monkey had to guide a visual cursor through an isometric joystick towards one of eight peripheral targets, either individually or together, to gain a reward. In the JA context, animals had to coordinate their force to jointly bring a common visual object to a target location. We analyzed recorded videos of monkey natural behavior during task performance, particularly focusing on their spontaneous head rotation toward the partner, as a measure of their joint action awareness. We found that the head rotations frequency toward the other monkey is significantly higher in the error trials, compared to successful performance. Importantly, these rotations were more likely to occur following errors during joint rather than individual action, providing evidence for their dyadic awareness of being committed in a JA task. Together, these findings will guide work on the neurophysiology of action monitoring during social interactions.