Not if the pocket watch is frozen too. That's popscience nonsense. Gravitational field energy is positive. See The Foundation of the General Theory of Relativity where Einstein said: "the energy of the gravitational field shall act gravitatively in the same way as any other kind of energy." If two bodies fall towards one another conservation of energy applies. Potential energy is converted into kinetic energy which is typically radiated away. But you don't end up with less energy that you started with.