Howard, 34, will play Kay, the longtime girlfriend of 45-year-old McConaughey's character in the mining drama about two men, who try to find gold deep in the uncharted jungle of Indonesia, said The Hollywood Reporter.
Together, their journey takes them from the mysterious riverbanks of Borneo to the high stakes boardrooms of Wall Street.
"Gold", directed by Stephen Gaghan, is midway through production in New Mexico after a production stint in Thailand.
The film shoot will wrap in October in New York. The ensemble drama also stars Corey Stoll, Toby Kebbell, Bruce Greenwood and Stacy Keach.
The Weinstein Co. Will release the film in the US.