  We present a spectropolarimetric study of the classical T Tauri star (cTTS)
LkCa 15 investigating the large-scale magnetic topology of the central star and
the way the field connects to the inner regions of the accretion disc. We find
that the star hosts a strong poloidal field with a mainly axisymmetric dipole
component of 1.35 kG, whereas the mass accretion rate at the surface of the
star is $10^{-9.2}$ $\hbox{${\rm M}_{\odot}$ yr$^{-1}$}$. It implies that the
magnetic field of LkCa 15 is able to evacuate the central regions of the disc
up to a distance of 0.07 au at which the Keplerian orbital period equals the
stellar rotation period. Our results suggest that LkCa 15, like the lower-mass
cTTS AA Tau, interacts with its disc in a propeller mode, a regime supposedly
very efficient at slowing down the rotation of cTTSs hosting strong dipolar
fields.
