In the title compound, C25H36N2O2, the two tert-butyl-substituted benzene rings are inclined at an angle of 53.5 (3)° to one another. The imidazolidine ring has an envelope conformation with with one of the C atoms of the ethylene fragment as the flap. The structure displays two intra-molecular O-H⋯N hydrogen bonds that generate S(6) ring motifs. The crystal studied was a non-merohedral twin with a fractional contribution of 0.281(6) for the minor domain.