The 67-year-old actor is starring as George, a historical figure inserted into the new fictional adaptation of Edgar Rice Burroughs' tale of a white man raised in the depths of an African jungle.

George was born in 1849 and fought as a teenager in America's Civil War and became one of the first prominent African American politicians before investigating atrocities carried out by Belgian officials against Africans in the Congo Free State. He died in 1891, aged 41.

And Samuel, who visited George's grave in Blackpool, England, last year (15) hopes that new movie will encourage people to study a man he believes should be far more celebrated by historians.

"Hopefully with this movie, we can persuade people to look into George Washington Williams' story and, through him, find out about that first holocaust in the Congo," Samuel tells Britain's Guardian newspaper.

During the period the Congo Free State was run as the personal fiefdom of Belgium's King Leopold II an estimated 10 million Africans died due to being subjected to forced labour and a brutal regime of mutilation and killings.

Samuel says he is enthusiastic about the real life humanitarian disaster being incorporated into Tarzan's familiar tale, saying, "Williams is in the movie trying to convince Tarzan, who hasn't been in Africa for 20 years, to go home and investigate King Leopold.

"He's talked to some soldiers that were there doing bad things and he wants to find a way to stop these things."

The veteran actor, who was honoured with a lifetime achievement prize at the Black Entertainment Television (BET) Awards on Sunday (26Jun16), is in awe of his character's adventurous life, which also saw him fight in Mexico, and become the first African American member of Ohio's state legislature.

"At 14 years old he (George Washington Williams) enlists in the civil war," Samuel explains. "Then he enlists in the Mexican revolution against the Emperor Maximilian. I don't know if he was an actual Buffalo Soldier, but I know he fought in the Indian wars too, and he killed a bunch of Indians! He was a Congressman, a preacher, a historian - he did a lot of things, he had a whole life, short as it was."

The Legend of Tarzan is released in U.S. cinemas on Friday (1Jul16) and debuts in the U.K. on 6 July (16).