  It is well-known \cite{mtbh} that {\em all} black hole solutions of General
Relativity are of Petrov-type D. It may thus be expected that the spacetime of
{\em physically realizable} spherical gravitational collapse is also of
Petrov-type D. We show that a radially homothetic spacetime, {\em ie}, a
spherically symmetric spacetime with hyper-surface orthogonal, radial,
homothetic Killing vector, is of Petrov-type D. As has been argued in
\cite{prl1}, it is a spacetime of {\em physically realizable} spherical
collapse.
