  We investigate the azimuthal angular correlation between the lepton
transverse momentum $P_\perp$ and the impact parameter $b_\perp$ in non-central
heavy-ion collisions, where the leptons are produced through two-photon
scattering. Among the Fourier harmonic coefficients, a significant $v_4$
asymmetry is found for the typical kinematics at RHIC and LHC with a mild
dependence on the $P_\perp$, whereas $v_2$ is power suppressed by the lepton
mass over $P_\perp$. This unique prediction, if confirmed from the experiments,
shall provide crucial information on the production mechanism for the dilepton
in two-photon processes.
