Rhys, currently appearing in The Edge Of Love, and Nia Roberts will play a Welsh couple who travel to Argentina to reassess their relationship. At the same time, an elderly woman heads in the opposite direction with a reluctant companion.
The film is described as a "Welsh and Spanish-language road movie" by Variety.
Rebekah Gilbertson and Oscar Kramer will act as producers. The script was penned by A Mighty Heart's Laurence Coriat.