Scottish actor Gerard Butler is to star opposite Hilary Swank in the big screen adaptation of Cecilia Ahern's best-selling book 'PS, I Love You'.

'PS, I Love You' tells the story of a young widow, Holly (Swank), whose late husband, Gerry (Butler), has left her a list of 10 monthly messages, which are intended to help her with the upheaval in her life.

The Hollywood Reporter says that 'PS, I Love You' will shoot this autumn in Ireland and New York.

The film reunites Swank with director Richard LaGravenese, who previously worked with her on the film 'Freedom Writers'.

LaGravenese, who co-wrote the script for 'PS, I Love You' with Steve Rogers, also wrote the screenplays for 'The Horse Whisperer', 'The Bridges of Madison County' and 'The Fisher King'.

Butler's other screen credits include 'The Phantom of the Opera', 'Lara Croft Tomb Raider: The Cradle of Life' and 'Reign of Fire'.