Ronan joins Gosling's fantasy film

Saoirse Ronan has reportedly become the latest addition to Ryan Gosling's directorial debut, How To Catch A Monster.

The Irish actress has apparently signed on for a role in the dark fantasy tale, reported Screen Daily.

Christina Hendricks is already on board to play a single mother-of-two, who is transported into a macabre and dark fantasy underworld when her teenage son discovers a secret road leading to an underwater town.

Ben Mendelsohn, Eva Mendes and Doctor Who star Matt Smith are also attached to the "modern day fairytale", which will mark Ryan's first stint in the director's chair.

Production on How To Catch A Monster is expected to begin in Detroit in the spring.

Saoirse, last seen in Joe Wright's Hanna, has a number of movies out shortly including Andrew Niccol's big-screen adaptation of Stephenie Meyer's The Host, Neil Jordan's Byzantium and Kevin Macdonald's film version of Meg Rosoff's teen novel How I Live Now.

She is also filming Wes Anderson's The Grand Budapest Hotel, where she has the lead role, and is set to play Mary, Queen of Scots, in a forthcoming period drama.