Primakoff effect in

We analyse data on forward $ \eta$ -meson photoproduction off a proton target and extract the $ \eta$ $ \rightarrow$ $ \gamma$ $ \gamma$ decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available $ \gamma$ p $ \rightarrow$ p $ \eta$ data for differential cross-sections and polarizations. We compare our results with present information on the two-photon $ \eta$ -decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies