  An interesting proposal has recently been made to extend massive gravity
models beyond dRGT by a disformal transformation of the metric. In this Letter
we want to note that it can be viewed as a mimetic extension of dRGT gravity
which enormously simplifies the Hamiltonian analysis. In particular, pure
gravity sector is equivalent to the usual dRGT gravity coupled to a constrained
scalar field. And we also give some comments about possible matter couplings.
