  We generalize Bell's hidden variable model describing the singlet state of a
two-qubits system by extending it to arbitrary states and observables. As in
the original work, we assume a uniform, state-independent probability
distribution for the hidden variables which are identified with the unit
vectors of a 3-dimensional real space. By slightly modifying our model, we
provide also a minimal hidden variable description of the two-qubits system,
relying on a single hidden variable. We discuss the main features and the
implications of the model.
