Joaquin Phoenix and Reese Witherspoon in "Walk the Line.""Walk the Line"/Twentieth Century FoxJames Mangold considered Joaquin Phoenix for Johnny Cash in "A Complete Unknown."Phoenix played Cash in Mangold's 2005 movie "Walk the Line."Mangold decided Phoenix would be too old and didn't want to service "meta-movie universe stuff," he told BI."A Complete Unknown," James Mangold's look at the life of Bob Dylan, almost gave us another taste of Joaquin Phoenix as Johnny Cash.Mangold, who previously directed Phoenix in his acclaimed performance as Cash in the 2005 movie "Walk the Line," recently revealed to Business Insider that he thought of calling up Phoenix to play The Man in Black again in his new movie.