The invention relates to a lamp assembly (1) for illuminating a surface (S) comprising a chamber (3) accommodating a plurality of light-emitting diodes (11R, 11G, 11B) capable of emitting visible light. The lamp assembly comprises diffusing means (12) capable of diffusing said visible light of said light-emitting diodes to produce diffuse light (D), and said chamber further accommodates collimation means (5) arranged to collimate at least a portion of said diffused light for illuminating said surface. The lamp assembly is especially suitable for ambiance and atmosphere lighting applications.
