Saoirse Ronan has joined the cast on Ryan Gosling’s upcoming feature directorial debut How To Catch A Monster. Sierra/Affinity handles international sales at the EFM.

Matt Smith, Eva Mendes and Ben Mendelsohn have also come on board alongside previously announced Christina Hendricks.

Principal photography is scheduled to commence in May in Detroit on the modern fantasy-drama set place against the backdrop of a vanishing city as a single mother’s son discovers a pathway to an underwater town.

Marc Platt and Adam Siegel produce for Marc Platt Productions with Gosling through his Phantasma Films and Michel Litvak and David Lancaster through Bold Films.