$tW$ production in run 2 of the LHC with ATLAS

We present measurements of the production of a $W$ boson in association with a single top quark using $pp$ collision data collected with the ATLAS detector at the LHC in run 2. The total production cross-section (with 3.2/fb of $pp$ collisions) and differential cross-sections for several particle level variables (with 36.1/fb of $pp$ collisions) are measured in final states containing exactly two leptons and a single $b$-tagged jet. Differential cross-sections (with 36.1/fb of $pp$ collisions) are also measured in final states containing exactly two leptons and two $b$-tagged jets in order to probe the modelling of the quantum interference between top-quark pair production and the production of a $W$ boson in association with a single top quark. These measurements provide important input to guide developments in the modelling of top quark production.