  We explore the possibility to explain the 750 GeV diphoton excess recently
measured by ATLAS and CMS collaborations in terms of a massive spin-2 particle.
In particular, we consider the case in which the top-quark loops can give the
similar amplitudes as the tree-level contributions to the diphoton and digluon
channels. Such a scenario can be naturally realized in the generalized warped
extra dimension models. As a result, the parameter space favored by the
diphoton data implies that the top-quark loop contribution can compete to and
even dominate over the tree-level amplitude in the spin-2 particle production
via the gluon-gluon fusion process. Similar results are obtained for the case
in which the spin-2 particle induces large invisible decay branching ratios, as
indicated by the ATLAS data.
