A gas turbine engine assembly is provided. The gas turbine engine assembly includes a core engine. The gas turbine engine assembly further includes a first rotor spool including a first fan assembly, an intermediate-pressure turbine, and a first shaft. The first fan assembly includes a single stage fan assembly coupled upstream from the core engine. The intermediate-pressure turbine includes a single stage turbine coupled downstream from the core engine. The first shaft extends between the first fan assembly and the intermediate-pressure turbine. The gas turbine engine assembly further includes a second rotor spool including a second fan assembly, a low-pressure turbine, and a second shaft. The second fan assembly includes a single stage fan assembly coupled upstream from the first fan assembly. The low-pressure turbine includes a single stage turbine coupled downstream from the intermediate-pressure turbine. The second shaft extends between the second fan assembly and the low-pressure turbine. A method of assembling the same is provided.