(CNN) A Hollywood studio executive once suggested that Julia Roberts should play iconic African-American activist Harriet Tubman in a biopic.

In a recent Q&A, screenwriter Gregory Allen Howard opened up about the 26-year journey to getting the "Harriet" biopic to the big screen.

At the time the effort started, he said, Hollywood was not the same.

"I wanted to turn Harriet Tubman's life, which I'd studied in college, into an action-adventure movie. The climate in Hollywood, however, was very different back then," Howard said. "I was told how one studio head said in a meeting, 'This script is fantastic. Let's get Julia Roberts to play Harriet Tubman.'"

Howard said when someone suggested Roberts could not play the role, the executive responded, "It was so long ago. No one is going to know the difference.'"

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