The disclosure herein describes a helicoidal system for securing a recessed light fixture assembly into an opening in a ceiling, wall or the like; the assembly comprises a light reflector having an upper collar and a light reflector support for mounting the light reflector into the opening of the ceiling, wall or the like. The light reflector support has an upper member that engages the upper part of the light reflector and has a helicoidal bearing surface to receive lugs provided on the light reflector whereby rotation of the light reflector, once received in the light reflector support, enables engagement in one rotational direction, and disengagement in an opposite rotational direction, of the light reflector to and from the reflector support.