  We determine to order alpha^3 the so-called residual mass in the lattice
regularisation of the Heavy Quark Effective Theory for Nf=2. Our
(gauge-invariant) strategy makes use of Numerical Stochastic Perturbation
Theory to compute the static interquark potential where the above mentioned
mass term appears as an additive contribution. We discuss how the new
coefficient we compute in the expansion of the residual mass can improve the
determination of the (MS bar) mass of the b-quark from lattice simulations of
the Heavy Quark Effective Theory.
