Charged gauge boson pair production at the Large Hadron Collider allows detailed probes of the fundamental structure of electroweak interactions. We present precise theoretical predictions for on-shell production that include, for the first time, QCD effects up to next-to-next-to-leading order in perturbation theory. As compared to next-to-leading order, the inclusive cross section is enhanced by 9% at 7 TeV and 12% at 14 TeV. The residual perturbative uncertainty is at the 3% level. The severe contamination of the cross section due to top-quark resonances is discussed in detail. Comparing different definitions of top-free production in the four and five flavour number schemes, we demonstrate that top-quark resonances can be separated from the inclusive cross section without significant loss of theoretical precision.