  The photospheric spot activity of some of the stars with transiting planets
discovered by the CoRoT space experiment is reviewed. Their out-of-transit
light modulations are fitted by a spot model previously tested with the total
solar irradiance variations. This approach allows us to study the longitude
distribution of the spotted area and its variations versus time during the five
months of a typical CoRoT time series. The migration of the spots in longitude
provides a lower limit for the surface differential rotation, while the
variation of the total spotted area can be used to search for short-term cycles
akin the solar Rieger cycles. The possible impact of a close-in giant planet on
stellar activity is also discussed.
