  Asteroseismology can provide information that is otherwise not easily
accessible, like the stellar mass and the evolutionary stage. Strong magnetic
fields are usually accompanied by rapid rotation, which makes asteroseismology
difficult due to spectral line broadening. We have found what may turn out to
be the Rosetta Stone of the stars: A slowly rotating solar-like star with a
strong magnetic field. We have recently detected solar-like oscillations in
this active sub-giant, but with amplitudes much lower than expected. We suggest
that the large-scale magnetic field alters the pulsations, which become
magneto-acoustic in nature. Here we present our results and discuss possible
implications and how this may open up a new frontier in the studies of magnetic
fields and stellar evolution.
