  We present the two-loop virtual QCD corrections to the production of heavy
quarks in the quark--anti-quark--annihilation channel in the limit when all
kinematical invariants are large compared to the mass of the heavy quark. Our
result is exact up to terms suppressed by powers of the heavy-quark mass. The
derivation is based on a simple relation between massless and massive
scattering amplitudes in gauge theories proposed recently by two of the authors
as well as a direct calculation of the massive amplitude at two loops. The
results presented here form an important part of the next-to-next-to-leading
order QCD contributions to heavy-quark production in hadron-hadron collisions.
