Perturbatively selected configuration interaction (PSCI) is used as a source of higher than pair clusters in the externally corrected coupled cluster method with singles and doubles (ecCCSD). This significantly decreases the dimension of the standard multireference (MR) CISD that is employed by the so-called reduced MR (RMR) CCSD method, thus enabling the use of relatively large active spaces. The performance of the proposed PSCI CCSD method is illustrated by considering the ground state potential energy curves of the HF molecule using DZP and cc-pVTZ basis sets (breaking of a single bond), and of the N-2 molecule using a TZ basis set (breaking of a triple bond). It is shown that notwithstanding a large reduction in the dimension of the external source, the accuracy of the resulting ecCCSD energies is almost the same as that obtained when correcting with the full MR CISD wave function.