ABSTRACT In historiography, the relationship between the Belgian socialist Hendrik de Man and King Leopold III has been addressed mainly in the context of what became the so-called ‘Royal Question’ after the war, that is, the question of whether Leopold's return to the throne was possible and desirable given his collaborationist attitude during the German occupation. The years before the Second World War have received much less attention, even though this was a period during which both men played no less remarkable a role, De Man as the spiritual father of the Labour Plan and as the protagonist of an authoritarian-led corporate state, and Leopold III as the king who, disillusioned with parliamentary democracy and its political elite, sought more and more support from the people. This paper pays attention to these themes that have faded into the background and to the sympathy that De Man and Leopold shared for a managed economy and an authoritarian populist monarchy. It does so first by outlining the divergent theoretical and ideological backgrounds of their thinking, then by examining their common ground, and finally by outlining the political scope of their alliance.