Shirley Barrett, who won the Camera D'or for Love Serenade in 1996, will begin filming South Solitary from her original screenplay in the second half of the year.
Gyllenhaal plays a secretive woman who travels with her uncle to a lighthouse island off Tasmania in 1928 and develops a relationship with a withdrawn war veteran played by Bettany.
Maximum holds worldwide rights excluding Australasia, where Icon is handling the release. Marian Macgowan and Sarah Radclyffe are producing and Emile Sherman serves as executive producer.
The Guitar was directed by Amy Redford and received its world premiere in Sundance last month. Saffron Burrows plays a woman who throws caution to the wind after she is diagnosed with cancer.
Redford produced with Bob Jason, Hayward Collins, Amos Poe and Brad Zions while Michael Roban served as executive producer through Cold Fusion Media Group alongside Damon Martin.
'Both The Guitar and South Solitary are wonderful movies for women and by women,' Maximum Films International's Charlotte Mickie said. 'The Guitar is an exuberant celebration of life and the senses while South Solitary explores how vulnerability can make us both foolish and strong. I think audiences will identify profoundly with both heroines played by Maggie and Saffron.'