  We report the first observation of Ly$\alpha$ pumped molecular hydrogen
emission lines in planetary nebulae. The H$_{2}$ emission observed in the
ultraviolet spectra of NGC 6853 and NGC 3132 can be explained by excitation of
vibrationally hot H$_{2}$ by Ly$\alpha$ photons. Constraints are placed on the
nebular Ly$\alpha$ emission profile, as well as the molecular hydrogen
temperature, column density and turbulent motion. These parameters are similar
for the two nebulae, pointing to similar physical conditions in these objects.
The ro-vibrational cascade following Ly$\alpha$ pumping is predicted to have
low surface brightness signatures in the visible and near infrared.
