  We propose that, in N=4 Super Yang-Mills theory, correlation functions of
certain 1/8 BPS Wilson loops and local operators inserted on a S^2 in
space-time may be computed in terms of analogous observables in the
"zero-instanton" sector of 2d Yang-Mills theory. The Wilson loops are mapped to
the standard Wilson loops of the 2d theory, as recently conjectured, while the
local operators are mapped to powers of the 2d field strength. We give several
perturbative checks of the correspondence, and derive from 2d Yang-Mills a
two-matrix model for the correlator of a local operator and a Wilson loop of
arbitrary shape. We show that the strong coupling planar limit of the
two-matrix model precisely agrees with a string theory calculation in AdS_5 x
S^5.
