Research has shown that the memory characteristics questionnaire (MCQ) can be used to discriminate between ‘memories’ of perceived events and ‘memories’ of imagined events. The present study extended this research by examining the utility of the MCQ in distinguishing impossible memories (i.e., reports of an event a person could not have witnessed). Congruent with previous research, a considerable number of participants in both the pilot study (45%) and the main study (44%) were willing to report that they had seen a non-existent film of the car crash in which Diana, Princess of Wales was killed. The MCQ ratings of three groups of participants were therefore compared: (1) those who indicated that they had seen the non-existent film, (2) those who were asked to imagine having seen the film, and (3) a control group who were asked to rate their memory of when they first heard the news of the crash. The MCQ did not serve to distinguish impossible memories, but there were reliable differences on one of the MCQ subscales between those who imagined the film and controls. Furthermore, participants who reported that they had seen the film gave higher scores on the Self Monitoring scale. Implications are discussed.