This is about the moment before the podium...

MARTIN Luther King Jr and Malcolm X might only have met once, but the work they did in the civil rights movement was monumental.

While we all know about their historic speeches, tireless campaigning and pioneering visions for the future of their country, many of us don't know much about the men themselves, their lives away from the podium.

But that's about to change with the arrival of Genius: MLK/X on National Geographic. The fourth instalment of the biographical anthology series follows previous seasons focusing on the lives of Albert Einstein, Pablo Picasso and Aretha Franklin, and offers an intimate look at the complex lives of Martin Luther King Jr and Malcolm X.

With Elvis and Chevalier star Kelvin Harrison Jr as King and Foe's Aaron Pierre as Malcolm X, Genius: MLK/X delves into the men behind the speeches, following their lives, from their formative years - including King's experiences in the Jim Crow-era American South and X growing up amid the deadly violence of the Ku Klux Klan and other white supremacist groups to the personal lives behind their essential civil rights work.

"It started with me watching interviews of him," says Kelvin, 29, of how he prepared to play Martin Luther King Jr.

"I was like: 'Should I start with the speeches?' - but then I wanted to go to more intimate things.

"I saw some stuff of him on talk shows, and I saw some stuff of him leaving buildings - archive footage of him leaving buildings and entering cars... and dinner, there was footage of him having dinner with his family.

"Those things are what I come to, because this is a show about the intimate spaces and the private moments of these men, not them, necessarily, behind the podium.