The theory of stellar evolution is at the basis of many topics of astrophysics. How do we know that this theory is correct? By comparing stellar models to observational data. The main limitation in this confrontation is that classical astronomical observations only give us access to properties of the stellar surface (temperature, luminosity, surface chemical composition). This is clearly insufficient in order to constrain a whole theoretical structure of the stellar interior, where complex physical processes are taking place. The only way to significantly improve our knowledge of the stellar physics consists therefore in directly obtaining observational constraints on the internal properties of the stars. This can be done thanks to asteroseismology, which is the study of stellar pulsation modes. Each mode of oscillation sounds differently the inner regions of the star and represents a valuable tool to probe stellar interiors. Asteroseismology offers thereby an opportunity to “see” inside stars and learn about their internal structure, an essential condition to better understand our universe.