In this work we have reported the controlled synthesis of gold nanoparticles into the surface cavities of P123 micellar assemblies together with the fluorescent dye molecules and investigated nanometal surface energy transfer (NSET) from confined donor dye to metal nanoparticles. The formation of hybrid spherical assemblies of P123 combined with fluorescent dyes and gold nanoparticles has been confirmed from HR-TEM, DLS, UV-vis, and fluorescence spectroscopic studies. The observed steady state as well as time-resolved fluorescence quenching of the confined micellar dyes present in the close proximity of gold nanoparticles which are attached to the surface of micellar assemblies, indicates efficient surface energy transfer from dye to gold (Au) nanoparticles. Since the NSET process is strongly dependent on the distance between donor dye and acceptor nanoparticles, successful applications of NSET require the perfect control over their relative location. Herein, we investigate the utilization of nanoparticles embedded self-assemblies of P123 for controlled NSET by tuning the precise location of donor dyes. Through the nanoencapsulation of the different fluorophore having different location inside P123 micelles, we have shown the corona region of P123 micelles as a perfect place for NSET and the core region as a barrier for NSET. Additionally, we have investigated the microenvironment of the confined micellar probe molecules in presence and absence of nanoparticles. This study further reveals that when the system changes from normal micelles to nanoparticles loaded hybrid micelles, unlike the probes C480 and C153, the anionic probe C343 undergoes a change in its location indicating the modulation of the properties of micelles in presence of nanoparticles. © 2012 American Chemical Society.