  Studying the internal structure of exoplanet-host stars compared to that of
similar stars without detected planets is particularly important for the
understanding of planetary formation. The observed average overmetallicity of
stars with planets is an interesting point in that respect. In this framework,
asteroseismic studies represent an excellent tool to determine the structural
differences between stars with and without detected planets. It also leads to
more precise values of the stellar parameters like mass, gravity, effective
temperature, than those obtained from spectroscopy alone. Interestingly enough,
the detection of stellar oscillations is obtained with the same instruments as
used for the discovery of exoplanets, both from the ground and from space. The
time scales however are very different, as the oscillations of solar type stars
have periods around five to ten minutes, while the exoplanets orbits may go
from a few days up to many years. Here I discuss the asteroseismology of
exoplanet-host stars, with a few examples.
