Grown-ups are always telling you about the dangers of smoking, but would you take more notice if the kids you look up to in school told you?
Well, a new study's found anti-smoking messages work better coming from the popular children at school.
The plan was tried out in 30 schools in England and Wales, and the results were compared with schools using other ways of passing on anti-smoking messages.
Kids in schools using the new plan were less likely to start the stinky habit.
Nearly 11,000 kids in 59 schools took part in the study.
Some of the schools tried out the new idea, while others used their normal ways of trying to stop kids smoking.
The children trying out the new plan were asked who they looked up to in school.
The new plan helped stop kids smoking
Then, the popular students were taught about the dangers of smoking, and encouraged to pass on the information to their friends.
Researchers found kids in schools trying out the new plan were much less likely to pick up the horrible habit than kids in schools using the normal methods.