  We discuss effects induced by beyond leading order contributions to photon
pair production. We point out that next to leading order contributions to the
fragmentation component of the signal lead to a change in the shape of
distributions. This is already mildly visible in present Tevatron data though
stringent isolation criteria tend to suppress the fragmentation component
considerably. We expect the effect to be experimentally confirmed in future
data samples with higher statistics which would serve as a precision test for
QCD.
