We report on the first compelling observation of α decay of 151Eu to the ground state of 147Pm. The measurement was performed using a 6.15 g Li6Eu(BO3)3 crystal operated as a scintillating bolometer. The Q-value and half-life measured are: Q = 1948.9±6.9(stat.) ± 5.1(syst.) keV, and T1/2 = (4.62 ± 0.95(stat.) ± 0.68(syst.)) × 1018 y. The half-life prediction of nuclear theory using the Coulomb and proximity potential model are in good agreement with this experimental result.