Blake Lively is set to star in film adaptation of 'The Husband's Secret'.

The 29-year-old actress has been cast in the CBS Films' new production based on the 2013 book of the same name penned by author Liane Moriarty, and will see her take on the lead role as Cecilia Fitzpatrick, according to The Hollywood Reporter.

And the production team believe Lively's ''vulnerability, strength and extraordinary talent'' makes her the ''perfect actress'' for the role.

Speaking about the casting, CBS Films president, Terry Press, said: ''Liane Moriarty has established herself as one of the defining voices of the modern woman, and Blake Lively's unique combination of vulnerability, strength and extraordinary talent makes her the perfect actress to realize Moriarty's creation.''

The blonde-haired beauty - who has daughters James, two, and seven-month-old Ines with her husband Ryan Reynolds - will explore Cecilia's reaction when she finds a letter from her husband addressed to her, asking her to open it but only when he has died, which he has not.

The curious spouse reads the note only to learn her partner has been keeping a major secret from her for many years, which makes her realise her marriage has been built on a bed of lies and murder.

The former 'Gossip Girl' star will be on hand to executive produce the movie, alongside Chris and Paul Weitz, as well as Andrew Miano.

Mark Ross and Alex Ginno are also on board the project and will be overseeing the project, which was turned into a HBO series fronted by Reese Witherspoon.

Meanwhile, more of Moriarty's creative works are set to be adapted for the big screen as Witherspoon and her 'Big Little Lies' co-star Nicole Kidman have optioned Moriarty's 2016 novel 'Truly Madly Deeply', whilst Sony have nabbed the rights to work on 'What Alice Forgot', which Jennifer Aniston is reportedly attached to.