The present work reports on the PbTe formation by swift heavy ion beam induced mixing of the bilayer of PbO and Te. Rutherford backscattering spectra (RBS) of pristine and irradiated samples reveal strong mixing with mixing rate at least an order of magnitude higher than that reported in other systems. X-ray diffraction (XRD) study reveals the formation of PbTe phase in irradiated samples, which is further confirmed by transmission electron microscopy (TEM). The observed ion beam mixing is attributed to the inter-diffusion of atomic species across the interface during transient melt phase, in the framework of thermal spike model.