`Hidden' symmetry of linearized gravity in de Sitter space

We demonstrate that the linearized Einstein gravity in de Sitter (dS) spacetime besides the evident symmetries also possesses the additional (local) symmetry $h_{\mu\nu}\rightarrow h_{\mu\nu} + {\cal E}_{\mu\nu}\chi$, where ${\cal E}_{\mu\nu}$ is a spin-two projector tensor and $\chi$ is an arbitrary constant function. We argue that an anomalous symmetry associated with this hitherto `hidden' property of the existing physics is indeed at the origin of `dS breaking' in linearized quantum gravity.