How a member of the Washington acting clan takes on the Ku Klux Klan PLUS TRAILER

Of all the fathers to follow in the footsteps of, Denzel Washington must be a tough one.

But John David Washington, the oldest son of the Oscar winner and his actress wife Pauletta, is not intimidated about walking the same path as his famous dad.

In fact he is so fearless he is taking on the biggest role of his career so far as the star of a new film directed by Spike Lee, who has worked with Denzel on numerous films, including Malcolm X and Inside Man.

"I'm just happy to continue the tradition," Washington, now 34, says with a smile.

"I actually worked for his wife [Tonya Lewis Lee] first. We did a film called Monster that played Sundance and she is the one who believed in me first.

"Spike had been tracking that and I guess he saw something.

"This is a guy I've idolised since I was a kid. He gave people of colour - men and women - a voice, a platform, and he chose me. I was beyond excited and just couldn't wait to get to work."

It was actually in a Lee film that Washington made his acting debut, at the tender age of six, when he had a small part in the biopic Malcolm X in 1992.

So he did not even pause to think when the filmmaker called him about a role in BlacKkKlansman, the true story of a black police officer who infiltrated the Ku Klux Klan in the 1970s.

"It was a phone call, very brief. He said, 'I got a book for you. Read it.'

"I was blown away, obviously, just by the fact this really happened and that this was a true story."

In the film he plays Ron Stallworth, the first African American detective in the Colorado Springs police department.

One day, he contacts the KKK over the phone after seeing an advert in a newspaper and poses as a white racist extremist.

To his surprise, he ends up being invited into the group's inner circle and recruits his colleague Flip Zimmerman, played by Star Wars actor Adam Driver, to pose as him and take his place in face-to-face meetings.

"This is a true story in African American history," Washington marvels. "A story that kind of slipped through the cracks.

"Nobody in my community was talking about this, nobody knows about this, it's not common knowledge. So I don't think anybody could be more responsible than Spike Lee and Jordan Peele [the writer and director of Get Out, who served as producer], to do this story. Nobody else could have done it."

As the investigation continues, Stallworth finds himself speaking on the phone to David Duke, who at the time was the Grand Wizard of the Ku Klux Klan.

This leads to some of the film's most absurd moments, even though Washington is obliged to use extreme hate speech.

"Spike really trusted me and I trusted the process," he says. "The confidence was rooted in the preparation and the kind of confidence that I gained as an actor, he's responsible for. It's beyond measure."

But while there are moments of humour, the film draws stark parallels to the issues that are still plaguing the modern United States.

Indeed its release in the US was timed to coincide with the one-year anniversary of the Charlottesville riots in Virginia, which began with white supremacists taking to the streets for a torchlight procession as they chanted "You will not replace us".

The film does not settle for thinly-veiled metaphors but instead makes overt comparisons and ends with footage from the deadly event, including of a car ploughing into the crowd and killing counter-protester Heather Heyer, who was 32.

Her last public Facebook post before she died read: "If you're not outraged, you're not paying attention."

It also includes footage of Donald Trump saying there were "very fine people" on both sides of the conflict and a clip of the real Duke saying the extremists were going to "fulfil the promise" of the US president.

For Washington, the unrelenting and violent footage is still tough to watch.

"Seeing it on the news, I obviously react to it. I was devastated. I was embarrassed, quite frankly, of our country.

"But we've almost become impervious to this sort of bad news."

He mimes double tapping Instagram posts on his phone, adding: "Our support is just 'liking' something. Scroll, like, scroll, like.

"But putting it in this movie - we're taking our time, we chose to be in this theatre, to see a Spike Lee joint.

"Then this footage is in the Spike Lee joint. It feels like it's at your doorstep and you don't feel as distant as if you're maybe watching it on your news feed.

"Because we trust Spike Lee, we trust his storytelling ability.

"The fact that he would put this in here makes it a little more real."

Now he is hopeful that the film will make audiences think.

"It depends on the people," he says circumspectly. "We'll see what the people say.

"I hope that it has an impact internationally. The language in this film is very hateful language but it's generational, and we're seeing that now that we have got a long way to go.

"So far the reactions have been great, especially towards the end. People seem to really feel how relevant the story is.

"Yes, it's a period piece but it has a very contemporary rhythm to it, and I think that was on purpose. Spike Lee's a master of tone and that's why I say nobody else could've done a film like this. And I'm very proud to be a part of it.

"If I can inspire one person to actually administer change, to want to inspire change, I will follow that person.

"I'm not asking the people to follow me. I'm trying to inspire somebody so I can follow them - tell me where to go."

BlacKkKlansman is released in UK cinemas now