The synergetic combination of anion photoelectron spectroscopy and highlevel relativistic coupled-cluster calculations was employed to study the anion, HThO-. The atomic connectivity of this anion was found to be HThO- and not ThOH-. Vibrational and electronic energy spacings in the HThO- photoelectron spectrum were measured and calculated, with good agreement between them being found. Computations yielded electronic energies and equilibrium structures as well as enabling orbital analyses. The adiabatic electron affinity (EA(a)) of HThO was determined to be 1.297 +/- 0.035 eV.