The Belgian "Generations Pact" contained a measure which aims at removing an inactivity trap for people who benefit from a survivor pension. In this paper we use a sample of administrative data from the "Datawarehouse labour market and social protection" and the microsimulation model MIMOSIS to assess the labour supply effects of this reform proposal. In a first step we estimate a standard discrete choice labour supply model for several subgroups. Subsequently we model the proposed reform in the tax and benefit rules and predict the change in desired labour supply of the targeted group. The proposed reform would have a significant positive effect on the labour supply of widows, but the effects are weak amongst low income survivor pensioners.