  We show that the sheets for a connected reductive algebraic group G over an
algebraically closed field in good characteristic acting on itself by
conjugation are in bijection with G-conjugacy classes of triples (M, Z(M)^\circ
t, O) where M is the connected centralizer of a semisimple element in G,
Z(M)^\circ t is a suitable coset in Z(M)/Z(M)^\circ and O is a rigid unipotent
conjugacy class in M. Any semisimple element is contained in a unique sheet S
and S corresponds to a triple with O={1}. The sheets in G containing a
unipotent conjugacy class are precisely those corresponding to triples for
which M is a Levi subgroup of a parabolic subgroup of G and such a class is
unique.
