A burner (1) for a gas turbine engine, having at the upstream end of the burner a heat source X for supplying heat and a high concentration of free radicals arranged to support a rapid and stable combustion of a main flame burning in a lean premixed air/fuel swirl in a combustion room defined by a quarl arrangement (4a -4c) axially aligned with the heat source (5) and positioned downstream an exit (6) of said heat source (5), and wherein a recirculation zone (20) of the main flame (7) directs a flow of free radicals back to a forward stagnation point (P) at the exit (6) of the heat source (5). The burner is provided with a fuel distributor (40) at the exit of the heat source (5), said fuel distributor (40) being supplied with liquid fuel and water and provided with mixing means (41, 141) for mixing said liquid fuel and said water for forming a fuel/water emulsion, and said fuel distributor (40) having means for directing said fuel/water emulsion to the upstream end of the main flame (7) for reducing the temperature of the main flame (7).