  We numerically investigate under which conditions the planet detected at 2.1
AU of Gamma-Cephei could form through the core-accretion scenario despite the
perturbing presence of the highly eccentric companion star. We first show that
the initial stage of runaway accretion of kilometer-sized planetesimals is
possible within 2.5 AU from the central star only if large amounts of gas are
present. In this case, gaseous friction induces periastron alignment of the
orbits which reduces the otherwise high mutual impact velocities due to the
companion's secular perturbations. The following stage of mutual accretion of
large embryos is also modeled. According to our simulations, the giant impacts
among the embryos always lead to a core of 10 Mearth within 10 Myr, the average
lifetime of gaseous discs. However, the core always ends up within 1.5 AU from
the central star. Either the core grows more quickly in the inner region of the
disc, or it migrates inside by scattering the residual embryos
