  In the Randall-Sundrum model, the radion-Higgs mixing is weakly suppressed by
the effective electroweak scale. A novel feature of the existence of
gravity-scalar mixing would be a sizable three-point vertex among the KK
graviton, Higgs and radion. We study this vertex in the process e^+ e^- -> h
phi, which is allowed only with a non-zero radion-Higgs mixing. It is shown
that the angular distribution is a unique characteristic of the exchange of
massive spin-2 gravitons, and the total cross section at the future e^+ e^-
collider is big enough to cover a large portion of the parameter space where
the LEP/LEP II data cannot constrain.
