One Battle After Another, the film starring Leonardo DiCaprio, Benicio del Toro and Sean Penn, has been 20 years in the making, according to its filmmaker, Paul Thomas Anderson.

DiCaprio stars as Bob, a paranoid ex-revolutionary living off-grid, who reunites with former accomplices as he's forced to confront an old nemesis after his daughter goes missing.

Director Anderson came up with the idea for the film, which also stars Teyana Taylor and Regina Hall, more than two decades ago, loosely inspired by Thomas Pynchon's 1990 novel Vineland.

DiCaprio, who won an Oscar in 2016 for survival epic The Revenant, told the BBC the film reflects what he sees as the growing polarisation in society.

"It holds a mirror up to society and talks about the divisiveness in our culture and the fact that there's so much polarity."

The Wolf of Wall Street actor explained that while he doesn't feel like there's a central message to the film, "there's an interesting undercurrent about extremism".

"It's political without making it feel like medicine," he adds.

The Usual Suspects actor del Toro plays martial arts instructor Sergio, who comes to Bob's help when he's under threat.

He explains that the film "says something about its time" but "it's also entertaining, fun and has a lot of heart".

Del Toro was most excited about having been able to work with DiCaprio, whom he has "admired and wanted to work with for many years".

"Leo and I are from the same class if Hollywood were a university - I've met him many times, and then finally we got a chance to work together.

"It's a dream come true, and he's very funny in real life and in the movie."

One Battle After Another is part political satire, part black comedy and part action blockbuster, and DiCaprio says overall the film "finds the humanity in all the central characters".

"It's about the people in the film and the characters - I'm a flawed protagonist - you can relate to them and their struggles and that's not an easy thing to do."

The Titanic star previously told Entertainment Tonight his character is the opposite of Tom Cruise in Mission: Impossible, as Bob "does everything wrong and doesn't land or stick any of his stunts".

'Surefire Oscar frontrunner'

The film has been warmly received by critics, with most of them awarding it five stars.

The Independent's Clarisse Loughrey hailed it as a "ferocious American masterpiece" that is "swaggering, funny and a timely action epic".

In a five-star review, The Guardian's Peter Bradshaw said the film's themes of "dissent, discontent and the lonely heroism of not fitting in" are made more interesting as "these ideas are very unfashionable in the US right now".

The Telegraph's Robbie Collin also gave a five-star review, and praised the acting.

"Penn is a knockout tragicomic villain: it's his best performance in years," he wrote.

He added that DiCaprio "astounds – frazzled and absurd yet also sweet and even noble, he evokes Jack Nicholson in his prime".

The Times's Kevin Maher awarded the film four-stars, calling it a "career high" for Shutter Island actor DiCaprio, adding the film is "a surefire Oscar frontrunner".

Maher said Anderson, operating with an alleged budget of $175m, was working on "his most ambitious canvas" and concluded the film has an "easy best picture Oscar nomination in the bag".

DiCaprio said that Anderson has "done a lot of films, but in this one, he really went for it".

Anderson also directed 2017's Phantom Thread and 2007's There Will Be Blood, both of which won Oscars.

Praising the filmmaker, DiCaprio called him "a visionary and seminal director".