Using a unique combination of two powerful experimental techniques, x-ray diffuse scattering (XDS) and coherent x-ray scattering (CXS), a heterophase fluctuation has been observed for the first time near the paraelectric to ferroelectric first-order phase transition in the relaxor ferroelectric (1-)Pb(ZnNb)O-PbTiO. This heterophase fluctuation, during which two phases coexist as if they are in a thermodynamic equilibrium state, acts as a precursor phenomenon for the phase transition. The CXS technique used here is still under development but shows promise for future study of heterogeneous solids.