We have developed a pressure-electrochemical cell apparatus to electrochemically insert hydrogen into metals at applied pressures of 1GPa. The coupling of pressure and potential (P^2) was motivated by our recent density functional theory calculations that predicted the stability of novel metal hydride phases when both pressure and potential are applied [1]. In this work, we adapted a traditional piston-cylinder pressure apparatus into a pressure-electrochemical cell by replacing the inert pressure transmitting medium with a proton-conducting liquid electrolyte (1M NaOH + polyvinyl alcohol) such that it not only provides hydrostatic pressure but also reduces into hydrogen, which is then absorbed into the metal cathode. The pressure being applied by the electrolyte was verified by measuring an increase in the electrical resistance of manganin alloy with pressure. We then electrochemically hydrogenated yttrium foil under varying pressures ranging from 0.25 to 1GPa, measuring the extent of hydrogenation post-mortem using x-ray diffraction. We find that the application of pressure suppresses hydrogen evolution, improving the current efficiency of hydrogenation of Y into YH3 from 45% at 0.25GPa to 75% at 1GPa. The development of the pressure-electrochemical apparatus unlocks a new pathway in potentially synthesizing novel metal hydrides.[1] P.-W. Guan, R. J. Hemley, V. Viswanathan, Proceedings of the National Academy of Sciences. 118, e2110470118 (2021).