  We investigate how strong gravitational lensing in the concordance LCDM
cosmology is affected by the stellar mass in galaxies. We extend our previous
studies, based on ray-tracing through the Millennium Simulation, by including
the stellar components predicted by galaxy formation models. We find that the
inclusion of these components greatly enhances the probability for strong
lensing compared to a `dark matter only' universe. The identification of the
`lenses' associated with strong-lensing events reveals that the stellar mass of
galaxies (i) significantly enhances the strong-lensing cross-sections of group
and cluster halos, and (ii) gives rise to strong lensing in smaller halos,
which would not produce noticeable effects in the absence of the stars. Even if
we consider only image splittings >10 arcsec, the luminous matter can enhance
the strong-lensing optical depths by up to a factor of 2.
