We use, for the first time, ab initio coupled-cluster theory to compute the spectral function of the uniform
electron gas at a Wigner-Seitz radius of rs = 4. The coupled-cluster approximations we employ go significantly
beyond the diagrammatic content of state-of-the-art GW theory. We compare our calculations extensively to
GW and GW-plus-cumulant theory, illustrating the strengths and weaknesses of these methods in capturing the
quasiparticle and satellite features of the electron gas. Our accurate calculations further allow us to address
the long-standing debate over the occupied bandwidth of metallic sodium. Our findings indicate that the future
application of coupled-cluster theory to condensed phase material spectra is highly promising.