A Hollywood movie studio executive once suggested that Julia Roberts could play Harriet Tubman, the 19th century escaped slave who is seen as an African-American icon.

Gregory Allen Howard, the co-writer of the new biopic "Harriet," starring Cynthia Erivo, said the idea was floated 25 years ago by a former movie studio executive.

"Picture 1994: 'This is a great script. Let's get Julia Roberts to play Harriet Tubman,' said the then-president of a studio sublabel," Howard wrote in an article for the Los Angeles Times on Tuesday, describing his long journey to bring Tubman's story to the big screen.