  Using the high energy color dipole approach, we study the exclusive
photoproduction of lepton pairs. We use simple models for the elementary
dipole-hadron scattering amplitude that captures main features of the
dependence on atomic number A, on energy and on momentum transfer t. This
investigation is complementary to conventional partonic description of timelike
Compton scattering, which considers quark handbag diagrams at leading order in
$\alpha_s$ and simple models of the relevant generalized parton distributions
(GPDs). These calculations are input in electromagnetic interactions in pp and
AA collisions to measured at the LHC.
