  We propose the complex group theoretical Clebsch-Gordon coefficients as a
novel origin of CP violation. This is manifest in our model based on SU(5)
combined with the double tetrahedral group, T'. Due to the presence of the
doublet representations in $T^{\prime}$, there exist complex CG coefficients,
leading to explicit CP violation in the model, while the Yukawa couplings and
the vacuum expectation of the scalar fields remain real. The tri-bimaximal
neutrino mixing matrix arises from the CG coefficients of the T'. In addition
to the prediction for theta_{13} ~ theta_{c}/(3 sqrt{2}), the model gives rise
to a sum rule, tan^2 theta_{sol} ~ \tan^2 theta_{sol,TBM} + (1/2) theta_{c}
cos(delta), which is a consequence of the Georgi-Jarlskog relations in the
charged fermion sector. The leptonic Dirac CP violating phase, delta_{ell}, is
predicted to be ~227^{o}, which turns out to be the value needed to account for
the difference between the experimental best fit value for the solar mixing
angle and the TBM prediction. The predicted CP violation measures in the quark
sector are also consistent with the current experimental data.
