And 22-year-old Jack is not the only big name being lined up to feature in the production, which is a screen adaptation of Sebastian Barry's best-selling book.
The Girl with the Dragon Tattoo star Rooney Mara will also take up a lead role.
IFTA winner Jack and American actress Rooney are currently in contract negotiations and will appear opposite veterans Vanessa Redgrave, Liam Neeson's mother-in-law, and Jeremy Irons, husband of Sinead Cusack.
Cork-born Jonathan Rhys Meyers and Academy Award nominee Jessica Chastain were initially cast for the film, but both had to pull out due to scheduling difficulties.
A source told the Herald that Jack's involvement in the flick will mean big things for him abroad as it will ensure that he is not typecast.
"This project will give Jack an opportunity to show his versatility and range," they said.
The Secret Scripture, released in 2008, follows Roseanne, who is uncertain of her age and recounts her journey in asylums in Ireland over 60 years.
As the story unfolds, audiences discover the why and how of Roseanne's incarceration and are also introduced to the second narrator of the novel, Roseanne's psychiatrist Dr William Grene.
The movie version, which has been in the pipeline for two years, will be entirely shot in Ireland and with an Irish crew - giving a further boost to the film industry as well as the Irish economy.
It is being produced by Noel Pearson, who is behind critically acclaimed movies My Left Foot and The Field. What Richard Did star Jack will join the cast on set in mid-October.
It's been a whirlwind few months for the good-looking Belvedere College graduate.
Jack has been jet-setting around the globe to promote Michael Bay's Transformers: The Age of Extinction for several weeks and has made stopovers in Hong Kong, New York, Miami, London, Berlin and Sydney.
He has been accompanied by his model fiancee Madeline Mulqueen.
Limerick girl Madeline, who got her first taste of fame when she appeared in rappers The Rubberbandits' music video Horse Outside, has been by her future husband's side.
Making the most of the promotional tour, the brunette has stepped out in an array of glamourous outfits on the red carpet to support her other half, including designs by Louise Kennedy. Earlier this month Jack travelled home for the Irish screening of the summer blockbuster and told the Herald he was overwhelmed by the support.