  We compute the top quark threshold contributions to the $\gamma\gamma$
production at the LHC. They appear when the invariant mass of the photon pair,
$M_{\gamma\gamma}$ just exceeds two times the mass of the top quark and induce
some feature in the $M_{\gamma\gamma}$ distribution. We determine the magnitude
of this threshold effect and characterize this feature with a simple empirical
fitting function to show that it is possible to observe this effect at the LHC
in future. We also explore some possible improvements that may enhance its
significance.
