Using phase-measurement interferometry, we observe the waveguide induced by a solitonlike optical beam sustained by the molecular reorientation-induced optical nonlinearity of a nematic liquid crystal in planar con-figuration. Our purpose in the study is to characterize the nonlocality of the optical response of nematic liquid crystals. A good agreement is obtained between the experiment and a full (2+1)-dimensional numerical simulation of the nonlinear optical beam propagation in the cell.