In summary, we employed a wave function in wave function embedding method to compute the electronic excitations of the NV -defect in diamond. This is the first time pDMET was employed for a charged species and the first investigation of the NV -defect using CASSCF/NEVPT2 for periodic supercell models. Compared to hydrogenated molecular cluster models, our calculations with periodic boundary conditions provide a more realistic description of the localized crystal defect. We observed a linear dependence of the NEVPT2-DMET energies on the inverse of the size of the embedding subspace and thus extrapolated to the non-embedding limit. The extrapolated triplet-triplet and singlet-singlet energy gaps for the large supercell are 0.1-0.2 eV within the experimental values. The vertical energy gaps of the singlet states with respect to the triplet ground state are also consistent with previous theoretical studies. We envision that extrapolations based on pDMET calculations can be used routinely in the future to study strongly correlated charged point defects in solids.