The increasingly high accuracy of top-quark studies at the LHC calls for a theoretical description of $t\bar t$ production and decay in terms of exact matrix elements for the full 2 > 6 process, including off-shell effects and quantum interference.
In this talk, I discuss how such effects can be consistently described beyond the narrow-width approximation using resonance-aware NLO+PS matching in the POWHEG framework. Using selected results in dileptonic and semileptonic channels, I demonstrate the impact of these effects on kinematic distributions sensitive to top-quark properties.