  Cross-couplings between a massless spin-two field (described in the free
limit by the Pauli-Fierz action) and an Abelian three-form gauge field in D=11
are investigated in the framework of the deformation theory based on local BRST
cohomology. These consistent interactions are obtained on the grounds of
smoothness in the coupling constant, locality, Lorentz covariance, Poincare
invariance, and the presence of at most two derivatives in the interacting
Lagrangian. Our results confirm the uniqueness of the eleven-dimensional
interactions between a graviton and a three-form prescribed by General
Relativity.
