Michael Fassbender has joined the cast of the long-gestating drama At Swim-Two-Birds for director-actor Brendan Gleeson.

It isn't known what character Michael Fassbender plays, although he joins a cast which includes Colin Farrell, Jonathan Rhys Meyers, Cillian Murphy, Gabriel Byrne, and Brendan Gleeson.

Brendan Gleeson will direct At Swim-Two-Birds from his own screenplay, which is adapted from the 1939 novel by Flann O'Brien. The story follows a teenage writer who fills his short stories with characters based on people in his own life.

Brendan Gleeson first acquired the rights to this novel seven years ago, and it seems this will finally go into production in spring 2012.