A light mixing module (3) for receiving light from a first set of light sources (4) and a second set of light sources (5), said light mixing module comprising: -an annular light guiding element (11), said annular light guiding element having an inner edge (13), a peripheral edge (12), a first intermediate surface (15) extending between said inner and peripheral edges and arranged to face said light sources, and a second intermediate surface (16) extending between said inner and peripheral edges opposite said first intermediate surface, wherein said inner edge (13) defines a cavity (18) with an opening arranged to face said light sources, wherein said opening is arranged to receive light from said first set of light sources (4) and said first intermediate surface (15) is arranged to receive light from said second set of light sources (5); and -a first reflective surface (17) arranged to close said cavity in an end opposite said opening so as to form a first mixing chamber (18), wherein said annular light guiding element (11) and said first reflective surface (17) is arranged in such a way that light entering via said opening is mixed in said first mixing chamber (18), coupled into said annular light guiding element (11) through said inner edge (13), guided through the annular light guiding element (11) in a radial direction by means of total internal reflection and coupled out through the peripheral edge (12), and light received by said first intermediate surface (15) is guided through said light guiding element (11) by means of total internal reflection and out-coupled through said second intermediate surface (16).