  The production of top-quark pairs in hadronic collisions is among the most
important reactions in modern particle physics phenomenology and constitutes an
instrumental avenue to study the properties of the heaviest quark observed in
nature. The analysis of this process at the Large Hadron Collider relies
heavily on Monte Carlo simulations of the final state events, whose accuracy is
challenged by the outstanding precision of experimental measurements. In this
letter we present the first matched computation of top-quark pair production at
next-to-next-to-leading order in QCD with all-order radiative corrections as
implemented via parton-shower simulations. Besides its intrinsic relevance for
LHC phenomenology, this work also establishes an important step towards the
simulation of other hadronic processes with colour charges in the final state.
