The electronic structure of an incommensurate Pb layer on Cu(1 1 1) is investigated by means of angle scanned ul-traviolet photoemission. Despite of the rather complex atomic structure with three competing periodicities, we observe a well defined band structure, reflecting essentially the fundamental (1 Â 1)-periodicity of the adlayer. Comparison with band structure calculations for a free standing Pb-layer shows that all observed bands can be fully attributed to the overlayer.