Babou Ceesay, star of Sky Atlantic's new drama, Guerrilla, has revealed that viewers will witness his character's evolution from struggling teacher to activist during the six-part series, which explores what it meant to be an activist within the British Black Power movement of the 1970s.

Ceesay, best known for his roles in Eye in the Sky and Half of a Yellow Sun, plays Marcus Hill, who liberates a political prisoner and forms a radical underground cell after facing pressure from his Asian wife Jas Mitra (Freida Pinto) to "do something".

He doesn't start out as a violent activist but soon finds himself at the forefront of the struggle against a racist police force, prejudice, nationalism and injustice.

Speaking at the London premiere of the show written by Oscar-winning director John Ridley and executively produced by Luther actor Idris Elba, Ceesay detailed the dehumanising experience his alter-ego goes through.

"I was kind of approaching it from an actor's point of view and trying to say he goes on this transformation over the six episodes. John (Ridley) said something really profound, that 'it's not so much a transformation – he becomes himself," he explained.

"The idea that you play a part in society and over time you let go of the things that – the façade – you drop the stuff, so the distance between what you think and how you are reduces, and that's a very beautiful way to put it. So over the six episodes that is riveting to me."

Pinto, who rose to prominence after starring alongside Dev Patel in 2008's Slumdog Millionaire, added that the Ridley's decision to have a mixed race couple at the centre of drama prompts larger conversations about diversity.

"It was interesting to see that within society there were mini-divisions," she said. "John so very delicately and beautifully adds this when I take Marcus to an Indian festival, and everyone is starring at him like 'what is he doing here? What is this outsider doing here?' Meanwhile we were all considered to be outsiders."

Guerrilla will air on Sky Atlantic from Thursday, 13 April 2017.