  We study the six-dimensional (2,0) superconformal field theory on S^1 x S^2 x
M via compactification to five dimensions, where M is a three-manifold. Twisted
along M, the five-dimensional theory has a half of N = (2,2) supersymmetry on
S^2, the other half being broken by a superpotential. We show that in the limit
where M is infinitely large, the twisted theory reduces to a three-dimensional
topological quantum field theory which is closely related to Chern-Simons
theory for the complexified gauge group.
