An LED luminaire, which comprises an LED array of LED elements and an optical element. The optical element comprises one or more partially reflective or partially transmissive elements, which are positioned to lie perpendicular to a plane of the LED array. In this way, the partially reflective elements create virtual sources or virtual LED elements, by reflecting part of the light emitted by an LED element, whilst allowing the original or “real” LED element to still be visible by partially transmitting the light.