Domhnall Gleeson has revealed his doubts over the At Swim Two Birds film.
His father Brendan Gleeson is planning to make his directorial debut with the big-screen adaptation of Flann O'Brien's novel, which Colin Farrell, Gabriel Byrne and Cillian Murphy have been attached to. It was originally set for release in 2010, with 14 drafts of the script already written by the actor, but has yet to start shooting.
"I think about it - worried but hopeful. You just never know. It's taken so long," Domhnall said.
"But then Dallas Buyers Club took years to get together and then ended up being superb. So it's about finding the right way to do it."
Domhnall, who stars in Frank alongside Michael Fassbender, is keeping his fingers crossed for the project.
"I may be too old to play any of the parts by the time it rolls around but we'll just have to wait and see. I hope, for my dad's sake, that it comes together. He's written a great script," he added.
The Irish actor, whose forthcoming roles include Angelina Jolie's Unbroken and Star Wars: Episode VII, plans to continue picking diverse roles.
"I don't want to be bored ever - ever - on a film set, because I'll just be terrible if I do that. But I can be terrible if I'm interested too - if you take big risks, you're going to fail sometimes," he explained.
"I just want to go to work interested, so I guess I try harder to get the ones that really interest me."
:: Frank is in cinemas now.