  We present the first calculation of direct photon production at
next-to-next-to leading order (NNLO) accuracy in QCD. For this process,
although the final state cuts mandate only the presence of a single electroweak
boson, the underlying kinematics resembles that of a generic vector boson plus
jet topology. In order to regulate the infrared singularities present at this
order we use the $N$-jettiness slicing procedure, applied for the first time to
a final state that at Born level includes colored partons but no required jet.
We compare our predictions to ATLAS 8 TeV data and find that the inclusion of
the NNLO terms in the perturbative expansion, supplemented by electroweak
corrections, provides an excellent description of the data with greatly reduced
theoretical uncertainties.
