This study uses a large field experiment linked to actual behavior to evaluate the effects of an information campaign with and without celebrity endorsement on the use of single-use plastics. We find that demand for single use plastics, particularly for plastic straws and spoons, is very responsive to information when — and only when — it is coupled with our celebrity endorsement. The effect of celebrity endorsement is sizeable. Subjects in the treatment with celebrity endorsement use around 29% fewer plastic straws and spoons in the shop at the end of the experiment compared with subjects in the control group. The impact of our one-shot intervention goes beyond the immediate effect measured right after the intervention. It remains significant and similar in size around one month after the intervention. Exploratory analysis suggests that an isolated information campaign affects attitudes, but not behavior, and that it is the celebrity endorsement itself that affects behavior.