  I present the main results obtained in a recent work together with Eduardo de
Rafael and Arkady Vainshtein on the hadronic light-by-light contribution to
muon g-2. We came to the estimate a^{HLbL}_\mu = (10.5 +- 2.6) x 10^{-10}.
Here, some emphasis is put in pointing out where the future KLOE2 two-photon
experimental program can help to reduce the present model dependence of
a^{HLbL}_\mu.
